When an airline goes bankrupt there are two options.
1) Either the plane continues on its route, and ends at the final destination. Sometimes going back to base afterwards with the passengers booked for the home leg. But often the homeleg can not be done because local creditors seize the plane.
2) The plane goes back to the home base mid-flight.

Which of the two happens depends on a multitude of factors. First and foremost obiously the ability to do so. When a plane does not have sufficient fuel to go back to base, then obviously the flight will continue.

Typically an airline would want to keep its assets on its home base. A plane makes a nice object for creditors to make a claim on. So a plane that gets stuck at a remote airport stands a good risk of local contractors (maintenance, fuelers, ATC, ground handling etc) putting a claim on the plane to force the swift payment of their services rendered.

Indeed… I have heard that the crew of one Braniff plane mutinied when the airline went bankrupt and diverted the plane to San Francisco… they continued to Honolulu as scheduled…