Why not give yourself a bit more time in FRA by taking a later flight? You still have the risk of a flight cancellation, but minimize the risk of a delayed TATL. Your profile shows A3 *G, so you can enjoy the lounge in FRA if you arrive as expected (and perhaps can switch to an earlier flight). I have had kind gate agents move me to an earlier flight, although I have no experience with this at FRA.

I just don't see the need to try and catch the early flight. Separate tickets on the same day is always a huge risk, but 2 hours is extremely risky if there are any delays.

Guys, come on! I'm quite confident that the OP knows about the risk of incoming flight being heavily delayed, being rerouted to BCN etc. He/she knows that and accept it as I read it, so stop lecturing.

Lets look at the facts here. The OP has EU passport; the chance that that incoming AC flight is cancelled or heavily delayed is low and still the OP has 2h05min at FRA, i.e. 1h:20min to clear immigration, pick up the bag and reach the check-in counters. If the OP has been to FRA before this is no issue at all. I bet the chance is more than 90% that the OP will accomplish that. I would book the early SK flight to CPH without hesitation. Waiting more than 8h at FRA to "be on the safe side" is ridiculous and a complete waste of time - just my cents.

If the OP knows all this already, why the question? Given that the OP already booked a 9+ hour layover in FRA, I don't see why that is an unreasonable alternative. It is already 1 hour less than what was originally booked! Also, most posts have been against what is being proposed...you do realize that you are in the minority?!?

The only benefit of taking the chance is that EU compensation could kick in (does it even work for a non-EU airline with the trip starting outside the EU?) and essentially pay for the cost of eating the cost of the missed flight plus the cost of the new ticket. Still quite a hassle.

Given that OP is looking for a cheap solution, taking a later flight compensates for any delay while allowing for the cheap youth fare. I am quite sure that an youth won't have a problem with a few hours of free wifi and food in the lounge, and perhaps a hot shower to shake off the Y long haul trip.

Btw, one of the key questions from the OP was whether the youth ticket could be rebooked after missing the flight. Was there a clear answer to this? (I assume that it is not possible)

I forgot to mention that I have done these sorts of connections in the past and really cannot recommend it. Just the stress of it all was regrettable, even if I have yet to miss a flight on a separate ticket. I prefer travelling to be enjoyable, so having to rush off a plane (from Y, not C), hurry through immigration/security and direct to the gate while lugging a carrry-on around is not my way of fun.

I fully understand that this will most likely work if everything goes as planned, but the downside won't be fun nor worth the cost of being cheap, IMO.

Please read the OP again. Final destination has changed. The 9+ hour layover was probably only option with original destination

Most post (me included) assumed the destination changes was on an inbound flight. We also made other wrong assumptions. Later OP corrected us, which at least for me changed the picture 180 degrees going from against to pro.

Well, there isn't really a change in the final destination. OP is still ticketed to BCN, but does not want to take the flight (eating the cost and risking LH re-pricing the ticket). I don't follow your claim that this isn't on the inbound/return flight, which the OP clarifies is in fact the case in Post 12. OP is simply willing to give up the FRA-BCN flight, right?

Unless I am completely missing something, OP wants to waste the cost of the FRA-BCN ticket and then risk missing FRA-CPH in order to save time...despite having no problem booking the original 9+ hour layover in FRA. OP already can likely not short check bags and will have to travel carry-on only, which may or not be a problem, in order to make a possibly tight connection at FRA. Unless I am totally mistake, FRA is a rather big airport and OP might be doing some running if there are any minor delays. I agree that this can be done if things are on time. Then again, how well does YUL handle snowy weather in mid-Feb?

The downside of this is the potential risk. OP is already throwing away the cost of the FRA-BCN ticket, risking the re-pricing from LH ( not sure how high the risk is, but LH used to be sensitive to this), possibly losing the FRA-CPH ticket if delayed (2 hours would be enough, also making it not eligible for EU comp) and then having to buy a new FRA-CPH ticket. Seems like a steep price to pay if things go sour.

I guess the confusion for me is why the 8 hour layover is suddenly such a problem when the 9+hour layover was previously fine. What suddenly became the rush to take these chances? I can only assume that the original ticket was quite cheap due to the layer, so money must factor in somewhere as well.

I can only wish the OP luck on trying this. At least we know OP is under 26, but I am too old and slow for this stuff:p. Curious to hear a report back (and happy to be proven wrong if it works).

Well, there isn't really a change in the final destination. OP is still ticketed to BCN, but does not want to take the flight (eating the cost and risking LH re-pricing the ticket). I don't follow your claim that this isn't on the inbound/return flight, which the OP clarifies is in fact the case a few posts back. He is simply willing to give up the FRA-BCN flight.

Unless I am completely missing something, OP wants to waste the cost of the FRA-BCN ticket and then risk missing FRA-CPH in order to save time...despite having no problem booking the original 9+ hour layover in FRA. OP already can likely not short check bags and will have to travel carry-on only, which may or not be a problem, in order to make a possibly tight connection at FRA. Unless I am totally mistake, FRA is a rather big airport and OP might be doing some running if there are any minor delays. I agree that this can be done if things are on time. Then again, how well does YUL handle snowy weather in mid-Feb?

The downside of this is the potential risk. OP is already throwing away the cost of the FRA-BCN ticket, risking the re-pricing from LH ( not sure how high the risk is, but LH used to be sensitive to this), possibly losing the FRA-CPH ticket if delayed (2 hours would be enough, also making it not eligible for EU comp) and then having to buy a new FRA-CPH ticket. Seems like a steep price to pay if things go sour.

I guess the confusion for me is why the 8 hour layover is suddenly such a problem when the 9+hour layover was previously fine. What suddenly became the rush to take these chances? I can only assume that the original ticket was quite cheap due to the layer, so money must factor in somewhere as well.

I can only wish the OP luck on trying this. At least we know OP is under 26, but I am too old and slow for this stuff:p. Curious to hear a report back (and happy to be proven wrong if it works).

There is a change of final destination. The flight YUL-FRA is a return flight. Most post were against the change because we assumed the flight YUL-FRA were the first flight with checked-in luggage, and therefore there were a risk of getting the return flight canceled. OP later corrected this wrong assumption.

FRA is a big airport with a stupid layout, but I still managed to transfer there several times in less than an hour arriving from RUH and connecting to CPH.

No one books a +9 hour layover on a single ticket unless there are no alternatives. If the inbound is late, it's the airline responsibility to get you on the next available flight and on top of this, you might get EU compensation.

Google flights shows YUL-LHR-MUC-BCN or YUL-LHR-ZRH-BCN in 12-13hr on Feb 24th, which is much shorted that what OP bought. Other options certainly existed. If the YUL-FRA is cancelled OP could be rerouted on either of the YUL-EU flights and miss FRA completely and still get OP to BCN before EU comp kicks in (in fact, OP might arrive earlier than expected).

Keep in mind, that the airline will get OP to the correct destination...which is BCN, not CPH. The separate FRA-CPH ticket will mean nothing to AC/LH. EU comp will only apply if OP gets to BCN 3+hour late, which pretty much means a cancellation due to the long layover in the current ticket. Any rerouting becomes a big problem as OP cannot predict which airport would be the transfer point, which was addressed earlier.

My comments were regarding the original none changeable and none refundable ticket YUL-FRA-BCN, and I still stand by that no one book a +9 hour layover if there is an earlier connection on the same route.

I guess we all have different risk aversions.

As stated above I would have booked a 2h05min at FRA without hesitation - and slept very good at night/not worrying about it.

If someone needs to be on the absolute safe side (in order to sleep well and not to stress) and doesn't mind to spend 8+ hours at FRA for a flight to CPH, please go a head, but don't lecture the young guy/OP that his initial idea/inquiry is crazy and too risky.

In my opinion, in 9 out of 10 cases, this would work and it would save both time and money for Nini_su, provided that Nini_su's not checking baggage. But in the 1/10 cases where it would not work, it could end up costing much more money and taking far more time than booking the later flight in the first place. So i'ts really up to Nini_su whether it's worth it to take the risk.

Let me also add that with a 9h connection in FRA, I don't think it will be difficult to short-check bags to FRA.

Let me add another option for the OP: Taking the train from Frakfurt to Copenhagen.

ICE772 leaves FRA at 08:42, with arrival Hamburg at 12:35. IC394 leaves Hamburg at 12:53 with arrival Copenhagen at 17:33. The whole journey is 8:35, and the price is 90 euros. So, he would be spending 8 hours on the train instead of 8 hours in the airport. The ticket cannot be used on any other IC train, but it can be used on other local trains, so the OP can get to Copenhagen with slower trains with the same ticket if he cannot make the 08:42 from FRA.

AC lets me short check bags when I have a plausible reason for wanting them to be short checked. But a 2-3 hour layover may be a harder sell to the AC check-in agent.

They will likely refuse to tag the bag to CPH when the transatlantic ticket is destined to BCN and not to/via CPH. While it’s possible to manually tag the bag, a request to do so in this manner will come across as rather suspicious and most airline reps will probably want to stay away from doing anything like this when the passenger is ticketed to go to BCN and not CPH.

No-showing for the FRA-BCN flight ordinarily results in the onward/return flights of the ticket being lost/out of sync with the ticketed PNR and it may turn out that buying a new ticket or paying significant fare change and fare difference costs comes into the picture if trying to use the rest of the ticket after getting to FRA. If willing to throw away the onward/return part of the ticket, then I would book the 9 hour layover and ask to short check the bag so I could pick it up at FRA. Have some reasons in mind why you would want your bag at FRA. ;)