Originally Posted by
rtalk25
Delta doesn't, but it charges a mile redeposit and change fee of $150, in case you find out you can't make that flight. That's over twice of Frontier. Plus to redeem Delta miles means transferring in DTW or ATL, which sucks for most markets in the east coast that are not those markets.
Delta's award availability is poor, the award search is maddening, and there is a fee (waived for Platinum and Diamond) for changing or redepositing awards.
Your remarks about routing through Detroit and Atlanta are uninformed, however. DL has about 2500 flights a day that neither end nor start in DTW or ATL.
US charges a fee for any award redemption, no matter how far in advance, and even if done online w/o an agent. Like fees for services, the future of FF programs is redemption with more points/miles and more fees.