Frontier Airlines offers free checked bags promotion in swipe at Southwest

Frontier Airlines took a swipe at Southwest Airlines' plan to start charging for seat assignments and checked luggage by doing the opposite.Budget carrier Frontier said customers can receive a bundle that includes a seat assignment and a carry-on bag without an upcharge if they book Tuesday through March 24 for travel through Aug. 18. The promotion applies for nonstop trips booked on Frontier's website or app.For flights departing May 28 through Aug. 18, Frontier said it would include a free checked bag.The ...