I combined SC and JP 2 weeks ago it is possible. It is also possible to combine Business Class and Comfort Class atleast its not greyed out or something and you can combine bottomless barrel and extra fuel tank too I just tested it.
First run last week or so
Düsseldorf SC,JP,SG,GD,D 73 Flights, 13 drops, 17,8%
Hamburg SC,JP,SG,GD,D 121 Flights, 19 drops, 15,7%
Cologne SC,JP,SG,GD,D 108 Flights, 18 drops, 16,6%
and today I have no clue how and why they are better ....
Munich SC,SG,GD,D 84 Flights, 18 Drops, 21,4%...
GI wrote on discord today:
Mr. Wrightheute um 11:29 Uhr
>Windows users got lucky tickets instead. Will they receive plane chests too
Make sure that you have updated to the latest version. (if you saw lucky ticket - it might be just graphical glitch)
Hopefully we will start sending lost...