According to Official Guinness Records,
On 26 May 2010, an X-51A Waverider successfully flew the longest, supersonic, combustion ramjet powered, hypersonic flight off the southern California Pacific coast. Launched from a USAF B-52 Stratofortress bomber and flying at 50,000 feet over the Point Mugu Naval Air Warfare Center Sea Range, USA, the Pratt & Whitney Rocketdyne air breathing scramjet motor burned for more than 200 seconds and allowed the Waverider to achieve the longest duration flight at speeds in excess of Mach 5.0. The test was the first use of a practical hydrocarbon fuelled scramjet in flight.
For a complete list of 2010 records, please visit 2010 Guinness Records in United States.