Ron Garret wrote:
I fly an airplane whose last two digits in its identifier are "0P"
(indicating that it's an OurPlane aircraft). Of course, OurPlane
would have liked it to be "OP" instead, but the FAA won't allow
"oscar" in aircraft identifiers, only "zero".

It happens that there's another airplane at my airport with the exact
same identifier identifier except that it ends in "SP".

What kind of planes are both?