During the latest Mastercard earnings call announced that as part of a renewed credit card partnership with Spirit airlines, a debit card would also be launched:
This quarter, we launched a new debit co brand card with Wyndham Rewards. And we renewed our credit co brand partnership with Spirit Airlines with an additional agreement to launch a new debit program with them in the future
I suspect we will see something similar to the Wyndham debit card.
Hat tip to URtheoneforme