UPS is quoting me a $70 fee for ground shipping a 40 lb. box. Southwest $-0- and that's for two boxes per traveler (i.e., 4 boxes). Extra checked luggage is $75 per piece. Besides the 50 lb. limit, there is also a 62" size limit with Southwest. Exceeding either of these will cost $75. While the 66 quart storage bins total 56", when I box them up I could threaten that limit.