To take advantage of the best prices you will need to prove you are a leisure traveller, on the way to the airport, so you will need to provide either yr flight numbers or yr holiday booking reference. I don't think you will need to provide this when you arrive at the station but you may be asked to give them on your journey from aldershot station to the airport.
Going to the airport by train is great, you can sleep, read (even at night), play a game, or just stare out of the window... The other caveat to buying these cheap tickets from aldershot station to heathrow airport is that there must be at least two grown ups travelling together. But another great advantage is that children go free. All kids under 5 go free, and then one child over five but under 16 per grown up travelling on the train to the airport.
make sure you leave enough time to get to the airport early enough to eat, shop and so on, so check the times of trains from aldershot station before you go. If you end up with time to kill at heathrow airport you can always read a book or play travel scrabble again! As you have bought yr train ticket in advance, you don't need to fret about the opening times of aldershot station.
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