Update 3/25/20: This offer has been extended through today, March 25, 2020. You must cancel by 11:59pm Mountain Time. I didn't notice if they also extended it by one day yesterday - perhaps they will continuously extend it by a day or two at a time to keep encouraging people to take action sooner rather than later.
Frontier Airlines has an interesting offer for those willing to proactively cancel upcoming travel: If you cancel by 11:59pm Mountain Time on March 23 25, 2020 for a booking that is scheduled for travel between 3/22/20 and 6/17/20, you can get a voucher good for $50 per person toward future travel. The $50 voucher can be redeemed through December 31, 2020, for travel through the end of Frontier's then available schedule (well into 2021). That's in addition to the credit you'll get toward a future Frontier flight in the amount of your unused ticket. This is an interesting incentive to encourage customers to cancel before Frontier is forced to cancel flights.
I noticed this offer while updating our Coronavirus cancellation policies resource page earlier today. At first, I didn't understand why Frontier would offer an incentive to cancel travel at a time when other airlines are offering incentives to book travel (in the form of flexible tickets). Then Stephen Pepper called it in an email conversation: Frontier is looking to avoid refunding you when they inevitably have to cancel flights due to reduced demand and/or travel restrictions. This policy incentivizes customers to agree to let Frontier keep their money (since you get a credit toward a future flight instead of a refund).
Here's the thing to keep in mind: if you cancel your flight today, you will receive a Frontier credit in the amount of the ticket that can be used within 90 days of cancellation. In other words, you'll have to book your replacement ticket within 90 days of the day you cancel - that booking can be for any time through the end of the available booking schedule. Currently, Frontier is allowing booking through 11/8/20. If you were to cancel on Monday, March 23rd, ninety days from that date would be June 21, 2020. That means you'll have until June 21st to book future travel and one would reasonably expect that the booking calendar will likely be extended into early 2021 by that point. It's therefore reasonable to hope that you'll be able to make use of that credit as we certainly all hope travel will be safe again by then.
The $50 credit then must be used for a reservation booked by 12/31/20 - again, since you can book through the end of the calendar, you should be able to use that credit well into 2021. Note of course that the voucher can only be used toward the fare of a trip (presumably not taxes and certainly not baggage, seat selection, etc).
Of course, the other problem is whether or not Frontier stays in business. We've already seen a couple of small US airlines that have announced an end to operations. Frontier is larger than those outfits, but much smaller than the major players. If domestic flight restrictions are implemented and/or Frontier just has to cancel too much because of low demand, it's not inconceivable that their financial position could become precarious. On the other hand, we surely all hope this passes us quickly enough to keep everyone in business. It's hard to predict the future at this point.
Still, this is an interesting offer, particularly for those who initially booked really cheap flights. If you had a booking that only cost you $40 or $50 to begin with, the risk is low in accepting that as a credit and also getting another fifty bucks for a future trip.
If I had an existing booking that was particularly expensive, I might hold out to get a refund or file a chargeback if necessary - but if my existing booking was pretty cheap, I might take them up on this. I don't have an existing booking - but if you do, this is worth consideration.