 Frustrated by the lack of progress, Soviet Air Force stopped all work on the K-15 system in 1959.Lessons learned with K-15 were used to develop new interceptor system requirements which led to the Tupolev Tu-28 interceptor.The abortive, trouble-filled development of La-250 was mirrored in the West by the similarly complicated creation of Convair's delta-winged F-102 Delta Dagger and F-106 Delta Dart interceptors, which however eventually resulted in operational weapon systems.