EasyBus
No-frills bus operator with routes from [Hendon Central station]? in north London to Luton Airport and Milton Keynes. Fares operate as on other "easy" brands like easyJet, where booking is only online and the earlier you book, the more likely you are to get a cheap fare.
Fares on easyBus start at �1 single and go up to �5 (the walk-on fare). The service is operated with minibuses, and if you have luggage you have to book an extra seat for it.
Note that it costs �2.50 single to get from Hendon into central London on the Northern Line, or �1.80 at weekends on an Oyster card. This can make the journey very cheap, but if the easyBus fare is more than �1 for the journey you want, it may be worth checking the fares for a [National Express]? or [Megabus]? coach service instead.