Mail delivery during the Christmas holidays of 1990 to U.S. troops stationed in Saudi Arabia for Operation Desert Storm was haphazard. So many letters and packages were mailed during the holidays, that warehouse space in Germany, which was the intermediate staging area for mail to Saudi Arabia, became full. Letters were often delivered weeks late, while packages were delivered with less delay. Airplanes flying between Germany and the Middle East have both a physical volume capacity and a weight capacity. A cubic foot of letters weighs more than a cubic foot of packages.

Required: Analyze the mail delivery system and offer a plausible explanation as to why letters were treated differently than packages.