These days, when the United States wants to deploy fighters to an operating theater, the logistics are actually very simple. The fighters take off, they refuel in midair, and then they land at an operating base. They may make some overnight stops, but they fly their way in, thanks to the impressive refueling capabilities of the 414 KC-135s and 59 KC-10s on inventory.
F-16s and other modern fighters simply fly to their operating theaters, thanks to aerial refueling, but World War II fighters didn't have that luxury. (U.S. Air Force photo by Master Sgt. John Nimmo Sr.)
But it wasn't always so simple, especially back during World War II. At that point, mid-air refueling had been done as a stunt, but there were no real practical applications. Most of the Army Air Force's fighters back then didn't have the range to regularly make non-stop flights. There were some notable exceptions, however. Bombers and the P-38 Lightning could usually make the flights across the Atlantic, typically via Greenland and Iceland.
This is how fighters arrived to the front before practical aerial refueling: By ship, in this case, USS Cape Esperance (CVE 88) is hauling F-86 Sabres to Korea. (USAF photo)
Most other fighters, including the P-51, couldn't make the journey. So, here's what they did instead. After the planes were built, assembled, and quality checked, the next step was to disassemble them and crate them. The crated planes would then be loaded onto a ship and taken to a port near the front lines. There, the planes were taken to a base, removed from the crates, and re-assembled. After yet another quality check, planes were ready to fly.
One of the risks of having a ship carry planes: Here USS Langley (AV 3, ex-CV 1) is being scuttled after she was attacked while ferrying P-40s to the Dutch East Indies. (US Navy photo)
Now, this could be a problem. You see, if the ship got attacked, the planes on board could be damaged. Or worse, the ship could be sunk. America's first aircraft carrier, USS Langley (AV 3) was sunk after it was used as an aircraft ferry.
See how a P-47 got ready for combat at the front lines in the video below.