Okay, I booked a flight because I wanted to fly the 747 service:
SFO-ORD-DEN-SMF

My flight leaves SFO at 6 am on Wednesday, my flight (COS-DEN-SFO) arrives Tuesday at 11pm. My questions are:

I will be checking a bag, unfortunately, I have heard that if I don't claim my bag, they will lock it up until I come get it, which would be the next morning when I go down to check in for my SFO-ORD-SMF (booked two different reservations). So when I arrive in SFO, can I just wait until the next morning to claim my bag?

Also, should I be forced to go down and retrieve my bag, will I be able to get back into security? Will an agent even check me in that early or can I check in online? If i print my boarding pass, will i get the error message when trying to print a bag tag with Mr. Chicken?

Also, what is the latest flight to get into SFO if anyone knows, or earliest (getting into SFO before 6 am) Maybe I can shorten the amount of time I have to stay overnight in SFO if I get an early arrival into SFO, or really late.

Thank you all very much.

Ok, I'm not entirely clear on what you're asking, so let me know if I have the picture straight. You are arriving in SFO late on Tuesday, have an early morning flight booked for Wednesday. You are checking luggage and want to leave your bag at baggage claim overnight instead of picking it up after your Tuesday flight. Correct?

If that's the case:

You are free to not pick up your bag at baggage claim, but that leaves it open to be misplaced or (even worse) stolen.

You can do online check-in for the Wed flight starting Tuesday 6am, so you can print your SFO-ORD-DEN-SMF BPs at that time. You have to leave the secure area no matter what to retrieve your bag, so you will have to reclear security after you pick up your bag and will probably need to check it on Wed morning. OLCI only asks if you're going to check a bag, you're still going to need to go to the counter. I am not sure I understand why you're checking a bag if your only goal here is to fly on the 747.

So long as you're flying COS-DEN-SFO, you don't have a choice as far as latest flight - it's just the latest DEN-SFO flight. Likewise I doubt you have any choice for your early Wed flight, since it's the 747 you want to fly right?

If you have them check in all the way, you do not have to worry about this.

Okay, so I will be arriving SFO at 11pm. If the ticketing agent can't check my bag just to SMF without following me to all these places (did it last year but I wasn't staying overnight in SFO) then I will have to either go down and claim my bag, or supposedly they will lock it up until I claim it. I wanted to know that if I go down to claim my bag, will the agent check it in that early even if I have my BPs? Or will security even let me through that early. I will be on summer vacation during this time which is the reason for me checking a bag, I will be away from home for three months. I just saw that UA does the 747 domestic SFO-ORD ORD-SFO routes daily and was determined to find a way to get on it.

Not wanting to be a killjoy, but a 3.5 hour ride on the 744 is absolutely NOT worth this routing, and an overnight 7 hour layover in SFO.

I have a brilliant idea. Get off the plane at SFO, claim your bag, get on a motel shuttle, check into cheap motel, sleep for five hours in a bed, get on cheap hotel shuttle, return to SFO, check bag, enter security, fly. The airport is not a campground.

Im 15...

I think it is, any flight is worth flying to me.

And its worth the segments and the upgrade.
This summer I'm doing:
SNA-SMF(Weekend)SMF-SNA (1 week later) SNA-DEN (Weekend) DEN-LAX SNA-DEN-SAT(2 weeks in SAT) SAT-DEN-COS(2 weeks in COS) COS-DEN-SFO-ORD-DEN-SMF (Two weeks in SMF) SMF-DEN-ABQ-DEN-SNA then my family is going to Jamaica ; LAX-BWI-MBJ-DFW-LAX

Is airside UA at SFO open all night? And will cops let a 15 year old camp out?

I've done it before, just never checked a bag on this kind of situation, with two different reservations. I called and inquired about this and the lady said that there is nothing they have against me overnighting in the terminal, however she doesn't know that UA will check me through that early. She is the one who told me that if I do not claim my bag they will lock it up until I claim it the next morning but I am apprehensive with that idea. Unless I just go down and just stay outside of the secured area until the next morning, I probably won't sleep much either way...

I wouldn't leave the bag at baggage claim, actually I wouldn't do any of what is described in this thread but if you must, I'd make sure you grab your bag. This would mean you'll be stuck landside though. The only good (well, less ridiculous) method here is to check the bags all the way through, its pretty easy and shouldn't matter that its two reservations they should still be able to do tag them through.

This sounds like a really bad idea all told though, you do realize the 747 isnt going away this year, this seems like a ton or effort, time and lack of comfort just to sit on a 747, and please tell me you're upgrading cause if you're doing all this to sit in the ghetto-Y that is 747 we might need to have your head examined

Oh the only reason I did go through all this was to be able to upgrade on this flight. I have an upper deck seat 13B right now. I wouldn't do that just to sit in the back, not even for E+!

I see a couple of problems with this plan

First, while they will lock up your bag if you don't claim it, I have no idea how easy/hard it will be to get it early the next morning. I kind of doubt that baggage services will be staffed at 5AM or earlier. So you're going to have to track down someone to open the office and get your bag for you. That will take time and especially in the extremely early hours of the morning may not be possible so you might have to decide between missing your flight and leaving the bag behind.

Second, at some point unclaimed bags get moved from baggage services near the carousel to some other location for processing. I don't know if they "purge" the office each night after the last flights or have some other rule, but you might find that your bag is hard to retrieve especially--again--that early in the morning.

My advise would be the hotel. I don't know that hotels necessarily have policies against 15 year olds checking in. I know I stayed in cheap roadside hotels in TX and the southwest as a 16 or 17 year old on summer road trips to visit friends, but that was quite a while ago so things may have changed since then.

If you can't get a hotel, have to check a bag, and can't check it through then I'd suggest you go ahead and claim your bag and head over to food court outside of security near the International terminal. There's usually enough activity in that vicinity even late/early that you won't be too alone and you might find some other international travelers camped out over there waiting for check-in or security to re-open in the morning.

Plus, after all that, don't forget about the possibility of the dreaded equipment swap. All that effort in vain.

Trust me, after all my years of flying UA I know not to get my hopes up on a certain equip. However, it looks like UA has this plane flying this route everyday, I am unsure if they are ferrying this plane everyday to go on an Int'l route or is this just a new domestic 747 with int'l config? I look at the flight stats everyday and I haven't seen them swap it...

Do you have to check a bag? Can't just do carry-on?

I would prioritize your options as:

1. carry-on only.
2. check bag through to final destination
3. Get bag from baggage claim, sleep in hotel.

I wouldn't advise just leaving the bag there to be picked up in the AM. At best you might lose a lot of time collecting it, and miss your flight. At worst, someone takes it.