To take benefit 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 give either yr flight details or your 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 provide them on your travels from chester station to the airport.
Going to the airport by train is great, you can take a nap, read a book (even at night), play a game, or just stare out of the window... The other caveat to buying these cheap train tickets from chester station to the airport is that there must be at least two adults travelling together. But another great benefit is that children go free. All children under 5 go free, and then one child over 5 but under sixteen per grown up travelling on the train to luton airport.
be sure to leave plenty of time to get to luton airport early enough to eat, shop and so on, so check the times of trains from the station before you go. If you end up with spare time at the airport you can always read a book or play travel scrabble again! As you have bought your ticket in advance, you don't need to fret about the opening hours of chester station.
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