An important point to make is that you can’t trust the prices you see quoted in advertising for last minute flights. This is because of the common practice of excluding booking fees, airport taxes and all sorts of other little extras from the price – these all get added on just when you’ve got your card out and you’re ready to pay, in the hope that by then you won’t want to back out.
Also, you should realise that just because a flight says it goes to a big city like London or Paris, it doesn’t mean that the airport is actually anywhere near. Budget airlines use smaller airports to avoid paying the higher airport charges at the larger ones, and these smaller airports can be as much as two hours away from the city centre by often unreliable public transport. In some cases, you can end up paying as much as you did for your plane tickets just to get a train to the place you thought was your destination.
On airlines that take bookings for seats, it is also worth noting that last minute flights will only have the seats that no-one else wanted, which usually means the ones in the middle of the row. This can be very important if you get airsick, or if you really want to sit together as a couple or family.
The biggest gotcha is that last-minute flights are always non-refundable. If you are going to buy one on impulse, make sure you can actually make it first, as there won’t be any backing out of the deal afterwards.
Copied with permission from: http://plrplr.com/65481/last-minute-travel-made-easy/