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