AFAIK selecting an airline in the pulldown list does not auto-select the airline code, whereas selecting airline code does auto-select the airline.

Sky Europe is entered in the database with an airline code of 5P, yet it seems the airline code is NE (or ESK for ICAO) and 5P is the Brazilian airline PENTA. Looking further, I notice Boeing's airline code for Air Europa is 5P - perhaps that is where it came from.

As there is an existing entry in the table I cannot edit the 5P code to NE. If you select 5P then if BA97 adjusts I imagine it will automatically adjust in your flight history also.