Just an idea and would be interested in people's thoughts..
Luton is rather constrained for a long list of reasons - this includes thing like number of overnight stands, and availability of slots in the first wave of departures form 0600 to about 0900. It does however have plenty of capacity to service departures late at night.
Easyjet has a base at Luton and as such is limited by the airport's constraints.
Easyjet fly London to Tel Aviv flies 14 times per week, taking about 5 hours, or arrives 7 hours after departure from London when you take into account the time zone. Ryanair and Wizz sometimes play the time zone game - what would stop Easyjet operating a departure about 11 pm form Luton to Tel Aviv (arriving 6 am local time) and returning at 7 am to arrive at Luton about 10 am local time ? Yes - I have checked that there are plenty of flights on other airlines from western Europe to Tel Aviv following a similiar schedule so there is presumably demand for flights 'overnight'.
Would have the advantage of avoiding the need for an overnight stand and could keep an aircraft busy overnight. Anyone care to comment ?