http://online.wsj.com/article/SB10001424052702303654804576345254232316730.html Travelers may find it just a teeny-tiny bit easier to redeem miles this year compared with last year, according to a new study of 24 different frequent-flier programs world-wide. Best among U.S. carriers: Southwest Airlines Co., which had award seats available for 99.3% of the queries made, and jetBlue Airways, which offered seats 79.3% of the time. Southwest and jetBlue both use points instead of miles, and IdeaWorks Co., the consulting firm that conducted the study, searched for award seats available at 25,000 points, the equivalent to standard awards at other airlines. Worst among U.S. carriers: US Airways Group Inc. and Delta Air Lines Inc., which didn't have seats available in about three out of every four requests. Still, both carriers showed large improvement over the past year, more than doubling their availability rates. Of 6,720 requests for award trips at standard mileage levels, typically 25,000 miles for a domestic ticket on U.S. airlines, 68.6% turned up with available seats, according to IdeaWorks. That's up slightly from 66.1% last year. The fact that availability increased at all is surprising: Airlines are eager to sell seats rather than trade them for miles due to high fuel costs. That said, it is expected to be especially tough to exchange miles for seats this summer because airlines are already heavily booked.