London Luton Airport Operations Limited (LLAOL) manage the airport on behalf of AENA and are responsible for security and infrastructure. They are not responsible for aircraft handling, baggage, ATC delays or fueling plus all the other things that can delay a flight. Interesting to know why you think the airport is to blame.
No formal responsibility but a big influence over operations as for security and infrastructure both play a role in the problems also.
Never said the airport was to blame but I am not used to such poor traveling experience which the UK as a whole offers to passengers compared to many airports accrues Europe