To be fair to David I think he raises a valid point about security and I don't think getting to the airport, one and quarter hours before departure is cutting it fine, especially if you are only travelling with hand baggage!
Many Low Cost Airlines only open check-in two hours before departure and can easily take 30+ minutes to drop the bags off and boarding passes (That is the same at many airports)...
So, by the time you have done check-in, you are in the realms of queuing at Security at around the same time David is, who has just turned up with his hand luggage.
Im not on here to knock Luton again, but I think us LTN fans forget, how much better facilities can be and are at other UK airports. Was at East Midlands the other week on a 6.30 departure and sailed through security in less than five mins and Birmingham a few weeks earlier and took no more than ten-fifteen minutes.
Birmingham is only marginally quieter than Luton and East Midlands is a fair bit more, but both airports were busy at the time and just shows they can manage their security queue flows at peak times and have enough lanes open to match demand.