UV light does not just create repairable dimers in DNA bases, it can and does rip DNA apart. Enough exposure would cause more than enough irreparable damage to kill the cell and 99% of the cell being destroyed is certainly not salvageable.
The Delta flight is cheaper. But check a bag at a cost of $25 for the first checked bag each way on Delta, and your total fare climbs to $256 -- more than the cost of the Southwest flight, which includes free first and second checked bags. Add a second checked bag for $35 each way on the Delta flight, and you'll pay a whopping $326.
Several major airlines waive checked bag fees for cardholders. For example, Delta SkyMiles cardholders can check one bag for free on Delta flights, and United MileagePlus Club cardholders can check two bags for free. (Restrictions and annual credit card fees may apply, and vary based on airline and type of card.