One of the most interesting things about old airplanes is the sense of history you can get, not only when flying them but also when maintaining them.

Airplanes come with a fair amount of official documentation:  manuals, logbooks, registration paperwork, modification reports, accident reports.  Many of the papers are maintained on file by the FAA, which has maintained the files of its predecessor agency, the CAA.

You can use this information to piece together an aircraft's history, and by also looking at the physical evidence on the airframe, you can build a picture of what the problems with the airplane were, how well the fixes were made, etc.

An airplane's maintenance and logbooks are also a slice of personal history for the owners and mechanics of the airplane.  You can see what was or wasn't important to a pilot by what equipment he added or removed from the aircraft.  Sometimes you find changes are made to the aircraft that weren't logged at all - rebel against paperwork or somebody who didn't care much about the airplane?  Mechanical modifications also have a style - some are very well done with high quality and care for the future, some are slapdash.

Old regulations required individual flights to be logged in the aircraft records, so you often can see a list of where flights went and how often the flights were made.  Comments in the notes provide glimpses of adventure.

For a historian of the history of technology it is also fascinating to observe how very little the experience of flight and the technology has changed over a period of 50+ years.  The basic technology of light aircraft was in place by the mid-30's and the same hardware, engine technology and aerodynamics are still completely familiar to modern mechanics.

The contrast to the brisk pace of current high-tech development is severe, yet during the 30's the light aircraft technologies were cutting edge and advancing just as quickly.  This pace continued until the late fifties - up until that time aircraft were often obsolete before they flew, particularly military hardware.

Without the strong hands of military and government regulation, will current high-tech industries go through a similar coagulation of standards and change as they mature?  Or will the government horn in and attempt to regulate the computer/high-tech industry and stiffle innovation?  One key difference is that the development costs of aviation have always been very capital intensive.  High technology development has been far less so, although some of the key advances did take place as a result of large-scale government funded research (such as the integrated circuit, much academic research behind computing architectures, and networking technologies behind the Internet).

It is interesting that in the past few years we're seeing a renaissance of general aviation and interesting digital technologies being applied to general aviation aircraft, such as integrated EFIS-like systems, global navigation, terrain avoidance, and electronic engine monitoring.  Most of these developments are being driven by the kitplane industry, which is applying off the shelf electronics and software components to aircraft needs.  The kitplane industry is largely unfettered by FAA regulations on airworthiness requiring costly testing and approvals of all equipment sold for aircraft.  Some of the systems are making it back into certified aircraft as the kitplane airframe manufacturers are gradually starting to produce new designs as certified aircraft.