What can I do at San Francisco Airport if I arrive at 11.35AM , and my connecting flight is at 3.35PM?
What  can I realistically do? Between collecting my luggage (Cathay Pacific,  from Hong Kong) and checking it back in to the following flight (US  Airways to Phoenix)?   I've never been to SF and would like to venture out for an hour or so  just to see the sights. Please advise! 
San Francisco - 6 Answers
Random Answers, Critics, Comments, Opinions :
1 :
You  really don't have as much time as you think you have.  You would not  get your luggage through customs for at least 30 - 45 min.  and you have  to be at the gate 45 min before.  If you leave the airport - you have  to go through security again which could add an additional hour if the  line is long.  See if you can schedule a longer layover - and take the BART into SF -  but that is underground so won't see much.
2 :
Realistically,  not much. It'll probably take you an hour to get your luggage and clear  customs, which makes it 12:30. You should check in and get your  boarding pass for the Phoenix flight right away, even if you're checked  in  you'll need to be back at the airport around 2:30. The 12:39 BART  gets to the Powell station downtown at 1:08, and you'd need to catch the  1:57 train to get back to the airport at 2:27. So you'd have about 45  minutes to look at (probably not ride) the cable cars, and soak up the  ambiance.  Beats hanging around the airport, I guess.
3 :
You will not  have enough time to leave the airport and see enough to bother. The  minute BART got you to downtown, you would have to head back.
4 :
You  should check your luggage straight through to Phoenix from Hong Kong  before you leave. Why would you have to pick up your luggage yourself  and take it over to U.S. Air?  You don't have enough time to go anywhere  really. It will be 12 p.m. by the time you get off the plane, and you  have to be check in at 2.30 p.m. You really dont have time to leave the  airport. So I suggest having a nice lunch and walking around after your  long flight.
5 :
you really don't have any time to go from  SFO to downtown and back you would need to check in to your 3:30 flight  about 45 minutes prior. So call it 2:30pm.  There is no real way to  check out SF in that short amount of time. The bart train 1 way from the  airport to down town is about a 25 - 30 min ride. So that kills an hour  already leaving you with 1 hour of time to look around.  I would suggest doing sight seeing another time.
6 :
Not much you can do ... I'd stay at the airport and shop and dine if I were you.... There is an airport / airplane museum / library if you want some peace and quiet... There's also a Moma store...
