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