Required to be in Aircraft :
"valid pilot certificate" (FAR 61.3a)
"photo identification" (same FAR)
"current and appropriate medical certificate" FAR 61.3c this means
driver's license if you are flying SLA
"appropriate and current Airworthiness certificate" (or special flight
permit) FAR 91.203a (see below)
""effective U.S. registration certificate issued to it's owner" FAR
91.203a (must be current owner...recent emphasis by FAA)
Documents you can be required to produce (but don't have to be in aircraft)
pilot logbook (be sure to have enough landings logged to make
passengers legal)
FAR 91.9 requires "current approved flight manual" (If one was not
required by certification, subsequently approved
manuals, markings, and placards are required.
aircraft logbooks
Aircraft airworthiness certificate has since be "regulatorily amplified" to
mean displayed at cabin entrance so it is visible
to passengers and crew"
above provided by legal counsel for AOPA in Dec. 2009 Issue of AOPA Pilot
magazine
Dan Caliendo
Ercoupe Mach 0.14
3658H