Scott Crossfield's missing plane

According to CNN, Scott Crossfield's plane is missing on a flight....
Scott (now 84) is considered the first man to fly faster than twice the speed of sound in an X-15>, in 19531
http://www.cnn.com/2006/US/04/20/georgi ... index.html
I hope it's just an emergency landing somewhere.
1 I want to think that it's a typo, since I believe that the X-15 is a product of the '60s, not early 50s. Possibly the X-5 Stilletto?
Scott (now 84) is considered the first man to fly faster than twice the speed of sound in an X-15>, in 19531
http://www.cnn.com/2006/US/04/20/georgi ... index.html
I hope it's just an emergency landing somewhere.
1 I want to think that it's a typo, since I believe that the X-15 is a product of the '60s, not early 50s. Possibly the X-5 Stilletto?