But now there's fear that what the government doesn't know could pose as a serious security risk.
The FAA has issued an order for every plane-- that's more than 350,000 aircraft-- in the U.S. to be re-registered. A dangerous amount of information is missing, and criminals are already taking advantage of the problem.
"I think it's a real problem. I mean the aircraft has to be registered for them to be air-worthy and legal," said John Jackson of Pacific Continental Engines.
The first letters went out to plane owners last month.
FAA officials blame the issue on sloppy paperwork. The FAA said that drug smugglers and other criminals are taking advantage of the problem by changing tail numbers on airplanes to throw authorities off track.
There is also the concern that terrorists could end up doing the same thing. But some people in the industry said even if the registration issue is fixed, the system will still be vulnerable to abuse.
"Even if you know who the aircraft's owners are there are many, many, many ways for ownership to be disguised, for the smugglers to buy the plane through any number of fronts and so forth," said David Warner of the National Aircraft Finance Association. "So you'd have absolutely accurate ownership information and registration information, but still the aircraft is easily being used by people who have bad intent."
Some people don't buy the safety argument and said that it's a money-grab by the FAA.
"Why do we need to spend more money to do something? I've got 20 airplanes, myself, and only half of them are flying. The rest of them are registered, they're in storage, they're waiting restoration," said plane owner Dennis Sanders. "It impacts the office staff, and we're having to keep track of all that stuff."
"They've just complicated the house--more paperwork, more people to take care of the paperwork. It makes the process longer," said another plane owner, Matt Jackson.
Owners will argue about it, but most will comply. Many of them admit flying is a love that is hard to give up, even if it means more paperwork and more fees.