IdeaWorks has researched the availability of rewards flights for its Switchfly Reward Seat Availability Survey including 25 different airline programs. More than 7600 booking queries across 280 specific dates during March 2015 were made to determine the results.
Airberlin's topbonus program came out on top with 100% total availability on reward seats in the survey. Closer to home, Virgin Australia's Velocity program was ranked as the top in the Asia-Pacific region and second in the world for overall reward availability.
Southwest Airlines tied with airberlin for first place, followed by Air Canada and Singapore Airlines to make up the top five.
Full results from the survey can be found here.