The Uniden scanner has a frequency range 25 MHz to 512 MHz, so it will receive air traffic control transmissions (which are 108 to 137 MHz here in the U.S.), and many many other transmissions as well, ranging from citizens band transmissions at the low end to UHF TV audio at the high end.
With the VHF Air Blade Indoor Model Antenna, I am able to receive air traffic control transmissions from an airport tower that is 15 miles south of my home. The terrain between my home and the airport is almost flat, though I am not in line-of-sight to the tower. There is another airport about 15 miles north of my home, and I cannot receive transmissions from its tower at all, because there is a very high hill between that airport and my home. Air traffic control frequencies do not pass through obstacles like hills or buildings, so the scanner's range -- with almost any antenna -- will depend on how flat the terrain is between the receiver and the tower. Transmissions from airplanes in the sky may be received over great distances, because there may not be any obstacles between the plane and the scanner. Since I can't tell exactly where planes are in the sky when I hear them, I don't know how many miles away they are from me. Also, the exact position of the antenna in my home affects the quality of my reception a great deal, in ways that are difficult to predict or explain. I get better reception when I put the antenna 10 feet inside the windows of my family room than I do when the antenna is next to the windows, and I get better reception still when the antenna is in the middle of my backyard. I understand why the backyard is a better place for the antenna than indoors, but not why 10 feet inside the windows is better than next to the windows.
