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.
Regional service for the airline is served by Delta Connection. Delta typically charges a fee for all checked bags on domestic flights, with most international flights having an allowance of one or two free checked bags per passenger, depending on destination.
As for the carry-on luggage, it must be within 45 linear inches. Delta baggage fees and restrictions vary based on flight destinations. Some destinations allow you to check your first bag for free, while others charge for every piece of luggage.