i would lease planes or buy the ones you have on lease. i agree with nick art

200 million? depends on the airline's size: I would be either investing in growing my airline with leases, if the airline already is at the size that I like it to be (100-300 aircraft, I prefer building quality airlines with some realism in contrary to spamliners) I start buying the aircraft, start investing in marketing, pay raises to get my reputation up to 100 and then save up to the necessary few billions to buy the replacement aircraft to not be dependant on leasing anymore. And that's basically it. Sometimes I build a little regional airline with a mini hub in the country, but apart from that after that the game get's pretty boring as there is no management required anymore.

i suppose i am unusual in this respect but i like to at around 8-10 yrs, keeps my reputation up and is good financially(maintenance). that also allows prices of up to 120m on a 10year old 767-300er

it would be fun but not possible