Delta Air Lines on Dec. 1 will no longer offer frequent flyer reward redemption opportunities on every flight

. Like other airlines, Delta allows loyalty program members to book reward travel on flights that do not have standard frequent flyer redemption availability by cashing in twice as many miles. Delta said the more flexible redemption option "will continue to be available on most Delta flights, but seats will be limited and possibly unavailable on some flights." Separately, the airline said some partner carriers would start imposing a surcharge when Delta's frequent flyers book reward travel on flights they operate.