Airports by rail, with Holiday Extras, who I work for. I am not making a commission on this (damn).

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 your 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 yr travels from harrow-on-the-hill station to the airport.

Going to the airport on the train is great, you can take a nap, read a book (even at night), play a game, or just gaze out of the window... The other restriction to buying these cheap train tickets from the 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 kidover 5 but under sixteen per adult travelling by train to the airport.

be sure to leave enough time to get to the airport early enough to eat, shop and so on, so check the times of trains from harrow-on-the-hill station before you go. If you have time to kill at the airport you can always read or play travel scrabble again! As you have bought your train ticket in advance, you don't need to worry about the opening hours of harrow-on-the-hill station.

You can get a tickets this way from harrow-on-the-hill station to Gatwick, Luton, Stansted, Manchester, Birmingham, Glasgow, and Newcastle. Holiday Extras don't sell train tickets from the station to Heathrow and some other airports, because you can't get one ticket to get you all the way there, boo! Damn you Heathrow Express!

Or maybe you meant

• Birmingham airport
• Glasgow International airport
• Gatwick airport
• Luton airport
• Manchester airport
• Newcastle airport
• Stansted airport