Taking the Earlier Flight

Q. I am going to Jamaica with my girlfriend this weekend. At the time I booked the flight, I was kind of rushed and distracted and I booked it for the evening. In the fullness of time, I realize that we will not be making it out of the airport and to our rental car before 8:30pm (flight arrives at 7:30). We then have to drive for 2 hours. Anyway, long story short, I would like advice on the best way to minimize cost of changing the flight time. Not date, just time. Are airlines often willing to do this at a nominal fee if there are seats available? How does one go about asking them to do this--does it matter?

A. Airlines usually charge for a confirmed same day flight change  and they're often higher for international travel than for domestic. For example, US Airways charges $50 for flights in the US and to Canada, Latin America and the Caribbean, and changes are only allowed to earlier flights, not later. However, if you wish to take your chances and fly standby for the later flight, there may be no charge. You're taking a chance with standby, since the earlier flight may fill up.

However, you could also do this to avoid the fee:  show up a couple of hours before the scheduled departure of the flight you really want to take and throw yourself at the mercy of the ticket agent. Maybe your original flight has been cancelled, in which case they will most likely confirm you on the earlier flight at no charge; or maybe it's oversold, so again it's in their interest to send you earlier in the day. 
We've been in situations where we've arrived at the airport earlier than we expected, and JetBlue, for instance, put us on an earlier flight with no fee. If you don't like the answer you get from one agent, and there are lots of them at the check in desk, you might try another person (maybe the one with the big smile) a little bit later.  Also, I'd check with the airline by phone to see if the earlier flight(s) are "wide open" or if it looks like they're going to be full; knowing that will help you know in advance what your options are.