I have had 2 flights booked with this airline and both got cancelled at the last minute. It looks like they cancel when they don't have enough passengers booked. Yesterday I was booked MCO-GSP and got a text about 2 hours before flight that it was cancelled and to read the email about what todo. I have still never received any email from them about the cancellation. I had to book a last minute flight on another airline and am out over $500 because of this useless airline. Again save your money and don't book with Frontier.

F9 does not have interline ticketing agreements. Thus, nothing to be done if it cancels other than go home or pay for a new ticket. That was a known risk. F9 will, of course, refund its ticket and the balance should be picked up by your travel insurance.

I am no fan of F9 and would only book them if there is nothing else available and I had an important meeting. But, your accusation that F9 cancels when it has low loads is not backed up by any evidence. While accusations such as this are made on FT about many carriers, it makes no sense. If MCO-GSP is cancelled, what about the passengers at GSP and onwards? Thus, I suspect that this is an accusation with no facts.

Yes Often1 I have no proof and would never be able to get proof but yesterday morning I told a friend I was afraid they might cancel because very light load up and back from GSP. The plane just flies MCO-GSP-MCO . A couple of months ago they also cancelled my GSP-MCO flight and it to had a very light load. Just looks suspicious!!!
I don't check to see how often they cancel these I just check on the days it effects me. Oh well I learned a good lesson and will never book another flight with F9

How do you know the load is light? Seat map is not at all a reliable indicator for an airline that charges for seat selection.

Yep - it happens all the time due to light loads.

Yikes, sorry to hear that this happened to you, OP. Any thoughts on the LGA > MCO route? How often does that one have a light load? Thanks!

Indeed, the business model relies on working the aircraft a lot and low turnaround times, all to squeeze that extra flight a day leaving at 5 a.m. or arriving after midnight. Many of the routes aren't "turns", so even if there's a low load on one segment, there are ones after that that have to be serviced. You also have airports like ATL where they only have two gates, so they don't want to leave 3 or 4 aircraft overnight there if they can prevent it.

Veddy veddy true. Lots of those empty seats will get filled in at the last minute because many people (especially single individuals) don't want to pay the fee.

Could Frontier have accomodated you on MCO-ATL or MCO-CLT at no charge, if they had service that day? You'd probably have to still get a one-way car rental which could be $100/day, but still better than $500 out of pocket on another airline.

At least out of MCO, Frontier should have a lot of staff working at ticketing.

On one hand, I'm sure you want to support GSP, but Frontier's schedule of 3x weekly is paltry. I'd only go on Frontier where they are a little thicker in frequency. More preferable is Spirit as they seem to have better service with re-accomodation for canceled flights but it doesn't serve GSP.

I was about to book with them on their newly announced flights from Newark to Cancun in the spring and did not because of this same concern.

I see a lot of reviews where this airline cancelled their flights right before and they were stuck in those cities.

If I buy a vacation package (i.e., a hotel resort in Cancun + tickets) and they cancel a few hours prior, not only I will lose my vacation (because the prices for the other airlines on such a popular route in the middle of spring break will be enormous), I will also lose at least some money I paid for the hotel, because even the most generous hotel cancellation policies allow canceling 1 full day before arrival, and more often it's 2-3 days before arrival, after which you lose at least the cost of the first day, if not more.

If they had these interline agreements with the other airlines this would make a huge difference. Because how can I risk like this for a family vacation? I would love to save money, but having this chance of just losing money and not being able to go on vacation at all is too much for me. I did not know anything about F9, saw really good price for the newly announced route to Cancun, but read about these cancellation horror stories and decided not to risk it.

While Frontier currently has one of the higher cancellation rates at around 3%, that still means you have pretty good chance of your flight operating on time. Some premium credit cards include good trip insurance that can get you a new flight at little or no cost to you. Each person should evaluate their options and tolerance for risk. I have flown Frontier enough and saved enough money that if I had to buy a last minute walk up fare I'd still be far ahead.

There is now a relatively inexpensive way of protecting yourself from cancellations on Frontier or other carriers that will not protect you on other airlines. Take a look at this post from a recent thread in the FT AA forum, which talks about the new service, "Freebird":

https://www.flyertalk.com/forum/31815208-post11.html

Bottom line is that high quality travel insurance can be purchased on a per ticket or annual basis. Some credit cards provide half-way decent coverage (but make certain that you read the policy itself and don't rely on marketing materials).

If you are going to fly a carrier which has no interline agreements and few, if any online reroute possibilities, either accept that you will occasionally be stranded or insure the risk.

US airports only I looked into Freebird and it said it was only for US airports I�m booked on a frontier flight from Cancun to Denver

To be frank, UA's prices are roughly in range with F9 and it offers twice daily nonstop and one inconvenient connection via IAH. Nothing to be done if there is massive IRROPS at either station, but if it is a question of one aircraft, chances are that UA can scrounge up a replacement at DEN while F9 simply doesn't have the extra aircraft lying around.

Either way. Check your travel insurance to make certain that it covers not only the cost of a new ticket, but the possible loss of a prepaid vacation or at least extending the vacation for a lost day or two.