From the manual:
As stated in the airline founding / creation page the airlines may not use names that are real world airline names or other trademarked company names, or names that very closely resemble those. The name and logo must be also within good taste and shall not be offensive in any way.
Real airline logos and liveries are also disallowed as they are usually trademarked by their owners.
Historical airline names may be allowed if it is certain that the name is no longer owned by any other company; it is the responsibility of the user to check this. But generally past airline names (such as Pan Am) are not recommended. Please create your own custom airline instead.
Well, this falls on that saying from law discipline that says you can do anything that is not illegal. There are many cases that players name their airlines with names that resemble real-life airlines in many degrees, and as the manual doesn't tell how close an airline name would resemble some RL airlines's name, the line that distinguishes copyright infringement is somewhat blurry.
For example, I cannot name an AWS airline as LATAM since its a trademark, but I can name as something similar as LANTAM or LATAIN.
For the case of classic airlines, note that the manual doesn't state that it's prohibited; it is allowed since you're sure that no one else possesses that name. In this case, I could name an AWS airline as VASP, Panair or Nordeste (former Brazilian airlines), as well as there's been a lot of AVIACOs and Interflugs around in game worlds. But another point to note is that it's up to YOU to use it and AWS will not be held responsible if someone that owns the name you're using complains.
In practical life, you'll be fine if you don't name anything as Ferrari. Ferrari is THAT company which witch hunts everyone who tries to build a miserable replica or uses its name for anything.