2006 $4.05 X-Plane
Issue Date: March 17, 2006
City: New York, NY
Printed By: Banknote Corporation of America for Sennett Security Products
Printing Method: Lithographed with hologram
Perforations: Serpentine die cut 10 ¾ x 10 ½
The X-15 rocket plane appears on this Priority Mail stamp. The X-planes were experimental U.S. aircraft created to test the technology of supersonic and space flight. The X-1 was the first plane to break the sound barrier (1947).