The top few for me - I've combined flights for airlines that fly under the same brand
x 112 - easyJet Group (Europe, Swiss, UK)
x 100 - Air Southwest (Not the US Southwest)
x 71 - Iberia Group (Mainline, Air Nostrum, Express)
x 67 - Ryanair Group (Mainline, UK, Buzz, Sun, Malta Air)
x 48 - KLM Group (Mainline, CityHopper, Asia)
x 39 - British Airways Group (Mainline, CityFlyer, Connect)
Dan