In 1943 FDR became the first US president to fly overseas. He was also the first president since Lincoln to visit the troops during a war, no president had ever left the country during war time and no sitting president had ever been to Africa. On January 9th, 1943 FDR embarked on a trip to meet secretly with Churchill at the Casablanca Conference. The word "Casablanca" was transmitted as the place of the meeting. The Germans intercepted this and translated it literally to mean "white house." They assumed the meeting was to take place in DC and not the Moroccan city.
This was long before Air Force One could take the president anywhere on the globe in luxury. He disembarked on the presidential train. Because this was a secret trip, it headed north as if he were going on one of his trips home to Hyde Park. The train stopped somewhere north of DC and came back south on another track. It continued on to Miami. Can you imagine how this disrupted travel in the states? In Miami he met up with a Boeing Clipper and flew across the Atlantic to North Africa.
Churchill's travels were shorter but probably more uncomfortable. He flew from England in a bomber. Two mattresses were spread across the bottom of the plane. He burned his toe on the heater while trying to sleep. Stalin was invited but declined due to the besiege of Hitler upon Stalingrad. De Gaulle showed but only because Churchill threatened to recognize Henri Giraud as the leader of Free France. This was the first time the two French leaders would meet.
The union of the two French leader did little to affect the progress of the war. The major accomplishments of Casablanca was the call for Hitler's "unconditional surrender". They also created the second front in France instead of the Balkans. One has to wonder if this would have happened if Stalin had shown up. Some say this is where the war started to take a turn toward the Allies.