How to merge airlines
From FSAirlinesWiki
The merger of airlines is occasionally allowed by the administrators, but only if the combined airline will have a value of less than 10 billion in total assets.
Do not attempt to transfer assets between airlines. Attempting to use the lease, loan, repeated sale of aircraft or any other method to transfer assets between airlines is prohibited and may result in the forfeiture of all assets involved in the transfer.
If you wish to merge airlines, both airlines must be partners and the CEO's/Presidents of both airlines should submit support tickets requesting the merger.
