Unable to create contract for AIRPORTS

Due to the shortage of Airports on WG I acquired an Airport corp to supply my Asset Maintenance corps. Now I find out that I can't sell airports to my companies. After I propose the contract, the message contract created appears but it does not show up on the contracts page.
It would be greatly appreciated if a GM could look into this.
Thanks,

I've got the same issue.
And I've lost two of Air transfer companies already.
it's display on the big map of country,
but however only appears one month,
and then gone next month.
Why do like that???
it doesn't make any sense.
fix it please.
Thanks. this's a nearly reality game,
buy just has some bugs need to fix.