There was recently a list of the top 10 Most Delayed Airlines from UK Airports

1. Wizz Air
2. Norwegian
3. Vueling Airlines
4. Thomas Cook
5. BMI Regional
6. Aurigny Air Services (Whatever that is ??)
7. Norwegian International
8. Eurowings
9. Turkish Airlines
10. Air Portugal

I personally have flown with No's 1,2 & 8 and they have all been pretty decent only delay was in Warsaw flying back with Wizz Air in 2015