My mother recently traveled to visit and had mentioned that wireless mice are recently banned from air travel? Also, is there a reason why?
Is that a flight policy or just a TSA standard?
There are no rules, either TSA, FAA, airline or otherwise, that would stop you from taking a wireless mouse (or most any other "transmitting" device) through security and onto a plane.
However once you're on the plane there are rules specific to radio transmitting devices, which a wireless mouse is.
With very few exceptions, the rules are broken into two phases of flight - take-off/landing, and cruise.
During take-off and landing, or specifically the period of flight when the plane is below 10,000 feet, no electronic devices are allowed to be used. That includes computers, wireless mouse, wired mice, kindles, MP3 players, etc. Specifically those devices need to be turned completely off. In the case of a computer, that means "off", not just "standby". In the case of a wireless mouse, that would also mean that the mouse would need to be turned off.
During the rest of the flight, electronic devices may be used, with some conditions. The largest condition is that any device with a radio transmitter must have the transmitter disabled UNLESS it is a specific approved type of transmitting device. On some aircraft - primarily those that provide inflight WiFi - computers with wifi are considered an approved transmitting device, and thus may be used. On most other aircraft, basically all transmitting devices are not allowed.
Specifically for a wireless mouse, this is a transmitting device, and thus technically is not allowed to be used during flight. It must be turned off completely when below 10,000 feet, and either turned off or have it's transmit function disabled above 10,000 feet. As you almost certainly can't (independently) turn off it's transmit function, that pretty much means it must be off the entire flight.
Realistically I'm sure everyone knows that the power output from a wireless mouse isn't going to be sufficient to interfere with the aircraft in any way, but the approach that has been taken is to simply disallow all transmitting devices, and then only allow those that have been suitably tested and approved. (Whether this approach is the correct approach is a conversation best had over a beer and not on Travel.SE!)
I believe it is actually an FAA restriction. You cannot have any transmitting devices operating on board of an airplane, that includes wireless mice and bluetooth headsets.
This is of course an in-flight restriction. It says nothing about actually currying the mouse in your baggage without using it. For some reason it wasn't clear to everyone.
Ok. Just to put a nail in this coffin:
So the basic premise is: Wireless devices can be carried on board and any device except the ones for medical use like insulin pumps either is or can be prohibited for use during flight.