N1 is used for executive transport for Department of Transportation, including the FAA, Federal Highway Administration, Rail Administration, Maritime Administration, and several other DOT agencies.
There are several photos of it, here on Flightaware. But the software disallows two-character registrations. So it cannot be labeled (and searched) properly.
N1-3 are the only two letter registrations in the world and we never expect to see them for flight tracking, so in the interest of tighter validation we’ve decided to require a minimum of 3 characters.
N4 through N9 are currently reserved. Considering that they may become assigned numbers in the future, would it be possible to have the program translate a Nx number into a 3 character registration by inserting a 0 (zero) after the N?
If I enter N1 the program translates to N03 as an example.
That seems very confusing. But more seriously it doesn’t really help the issue.
We realize our current policy causes an issue for the photographs of these three planes. We know that military registrations (all numeric) are also an issue.