Visa for domestic flights

It's expired......How long ago did the Visa expire. ??

Your  illegally in the country, and need that job.    Looks like they've got you over a barrel.
Who knows what the domestic airline counters “key in “ to the terminal upon checkin.  Personally, I've never noticed them turn pages looking for a current visa,,maybe the computer has that recorded.

Either way,,they hold all the cards now.   If your blacklisted for overstaying ( see other threads on this ) it can be $4000 to get your name off that list.   I've heard that the fine for overstaying can be anything up to $30 per day ,,but since the place is rotten with corruption,,they'll shake you down for what they think you can pay.

BUT..you've got big problems ahead. Hotels at the destination usually check current visa validity, along with banks ,phone companies, apartments etc etc .  Getting the new VISA is the main priority now.

What you do from here is purely up to the discretion off the immigration people here.
Good luck