Answered by The Penny Pincher
Although it is not possible to predict with certainty what effects a bankruptcy will have on an airline, past precedent would seem to indicate that Delta SkyMiles members should feel secure earning and holding their SkyMiles. Both United Mileage Plus and US Airways Dividend Miles members did not experience any mileage loss when those airlines entered bankruptcy.
In my opinion Delta is too large of an airline to cease operations altogether. Therefore, unused tickets, unused miles, and unused awards will remain valid with Delta Air Lines or one of their SkyTeam Partners.
Thanks for the question,