In the United States Air Force, General of the Air Force is the highest commissioned officer rank, and therefore the highest overall rank as well.
The insignia of the General of the Air Force is as follows: Five interconnected silver five-point stars arranged in a circular pattern. The pay grade is the same as that of General, O-10.
The rank of General of the Air Force has been held by only one person in history: Henry H. Arnold.
There are equivalent ranks in both the United States Army and the United States Navy, they are General of the Army and Fleet Admiral respectively. The field marshals of Great Britain are also equivalent.
The rank of General of the Air Force and their equivalents in the United States Army and United States Navy were created by public law 482 of the 78th congress, passed on December 14, 1944. The ranks were originally intended to be temporary, though they were made permanent on March 23, 1946 by an act of the 79th congress.
'Five-star' ranks are attainable only in time of war, and only by senatorial appointment. In December 1944, seven men gained a fifth star.
It is not coincidental that these ranks are equivalent to the highest rank attainable in Great Britain. At the time of their creation, there was friction between the military leaders of the United States of America and those of Great Britain, the so-called 'five-stars' were intended to reduce that friction.