American warplanes are being equipped with electronic tags, so that aerial tankers can automatically note who got what when they are refueled in flight. These records used to be updated manually, which led to errors, and a distraction for the boom operator who was handling the refueling operation.
The electronic tag is called RFID (radio-frequency identification), and it's been in development for years, to replace bar codes (which was the previous revolution in keeping track of stuff). RFID uses small labels containing a cheap (less than a buck now, headed towards pennies each) electronic device that contains information about what is inside whatever it is attached to. The RFID is written to by a PC equipped with RFID writer hardware and software, or, in the latest generation of RFID chips, via a wireless device. What makes it all work is the ability of RFID to broadcast back when an electronic RFID reader is within range (3-4 meters, or at least ten feet) of an RFID tag. The RFID tag requires no power, it simply reflects back when hit with electromagnetic energy from the RFID reader, sending the data placed on the tag back as well. You then plug the RFID reader into a PC and transmit the RFID data back to a central database that is updated. The air force tanker version ( ARAI, or Automatic Receiver Aircraft Identification) has a longer range, as the refueling boom is about 12 meters (39 feet) long, and the aircraft is often 20 meters away (if booms attached to the wings are used.)
The way the military uses RFID, anyone with a PC and a password can get on the Internet and access the database to see where their stuff was the last time someone came by with an RFID reader. Unlike bar codes, which have to be visible to the reader, you can have a container full of individual items, each with its own RFID tag, that can be read when the RFID reader goes by. Some readers can also write to tags, and some readers have a range of up to a hundred feet. There are several generations of RFID equipment in use at the moment.
While RFID is still too expensive for most manufacturers and retailers, it has become cost effective for smart credit cards (especially outside the United States) and for things like passports (inside the United States). It's very economical for ARAI. Moreover the military has found RFID extremely effective in solving the ancient problem of tracking goods that enter the normally chaotic military supply system.
One of those goods being moved around is the jet fuel carried by aerial tankers, and it also has to be kept track of. The air force has to keep track of what fuel goes to what aircraft and when, to enable more efficient use of the tankers. ARAI is still being tested, but, so far, it works.