Tarbert says it's possible that some regulation recommendations could be produced by July 2008, although he calls that "a big, big if." Even then, a Notice of Proposed Rulemaking wouldn't "hit the street" until a year later, and a public comment period of 90 days would follow after that, so any regulations likely wouldn't come into play until the middle of 2010.

One problem is that there's no definition yet for what a small unmanned aerial system is. MITRE Corp. has taken a stab at defining it for the FAA, and Charlotte Laqui, the UAS project team leader for the company, also spoke at the Wednesday meeting.

Stressing that the definition is just a "starting point," and certainly hasn't been accepted by the FAA, Laqui says MITRE has roughly defined possible operations for two classes of small vehicles.

One would have a maximum weight of four pounds, a flight ceiling of 400 feet above ground level and could fly in all classes of airspace. Such vehicles could fly over even heavily populated areas without posing a big risk to people on the ground or other vehicles in the air. Another class of vehicle could weigh up to 35 pounds, fly up to 1,200 feet above ground level only in Class G, or uncontrolled, airspace. Those vehicles would pose an acceptable risk in more lightly populated areas.

Vehicles could not operate within three miles of a chartered airport and would have to be kept within sight of the operators, she says.