The fact that Delta is already in bankruptcy lends towards the fact that if the pilots do choose to go on strike, there is a good chance that the company will be forced out of business, since they would not be able to have enough revenue to operate currently in the future.
That said, the union should be more aware of the positioning of the company than we are. If there is indeed a good chance that the company would go out of business, I would hope that the union makes an intelligent decision and decides not to strike. If the strike leads to Delta going out of business, not only would those pilots not have the salary/benefits they want, they would no longer have a job, and they would have a difficult time finding jobs elsewhere.
That said, unions have unfortunately made less than stellar decisions in the past which HAVE led to huge losses of jobs. It all depends on whether or not they decide to call the company's bluff. Given the state of the industry and the bankruptcy, I hope they don't.
Ok, that said, if they go on strike, and the company is still in business, then you should be able to switch your ticket to another airline at the Delta ticket counter (good luck-- everyone else will be trying to do the same thing)
If the company is no longer in business, the other airlines will, by law, have to honor your ticket for a max fee of $50 each way STANDBY. That means that you will only be traveling standby, and so will every other person who is booked on a Delta flight. You will likely be repeatedly bumped from flights, and it could take several days to actually get on a flight.
If you end up losing your entire ticket value, there is a way to get your money back as a creditor, but you are an unsecured creditor, which basically puts you last in line for getting paid (i.e., don't hold your breath).
If I had Delta tickets, I would just sit tight and see what happens. I wouldn't try to change my ticket or anything, because I really don't think there will be a strike. If there was a strike, I'd try to buy a sort-of-cheap ticket from Southwest, and just forget about my Delta ticket, because I wouldn't want to deal with the hassle.