To take advantage of the best prices you will need to prove you are a leisure traveller, en route to the airport, so you will need to give either your flight numbers or yr 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 give them on yr travels from the station to the airport.
Going to the airport by train is great, you can take a nap, read (even at night), play travel scrabble, or just gaze out of the window... The other restriction to buying these inexpensive train tickets from lincoln-central station to the airport is that there must be at least two grown ups travelling together. But another great benefit is that children go free. All children under five go free, and then one kidover 5 but under sixteen per adult travelling on the train to heathrow 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 lincoln-central station before you go. If you have spare time at the airport you can always read or play a game again! As you have bought your train ticket in advance, you don't need to worry about the opening hours of lincoln-central station.
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