No, there is no mechanism to attach them to the aircraft.
Yes and no. Boeing makes multiple models of both aircraft. It really depends on the model. To answer in short the largest Boeing 777 in production is longer and wider than any 747 ever made to date. The 777-200s and 777-300s are currently the largest Commecial Airliner Boeing makes, however Boeing has indicated that a few new models of the 747 are on the drawing board that may bring it back to the top of the chart. See Boeing's Website (They provide detailed specs and diagrams)
A Jumbo Jet is any Boeing 747.
like any other plane
Air Force One is the call sign used describe any aircraft carrying the US President, so in theory Air Force One could be any type of aircraft. The official Presidential fleet consists of two customised Boeing 747s, either of which may be colloquially referred to as Air Force One. However this only becomes the official designation when the President is on board.
The Boeing 747 was developed by a team of designers and engineers. Initial development was in response to a military bid for a heavy lifter transport aircraft. When Lockheed won the contract with their C-5 Galaxy, Boeing took parts of their proposed design and, adding to it, developed the 747. If there was any one person who first "thought" of it, his or her identity has been lost in the mists of aviation history. Historically, Juan Trippe (head of Pan American World Airways) had been pressing Boeing for a transport bigger than the 707 for some years, and Pan Am bought the first 20 B707s. However, Mr. Trippe does not get the credit for the specific aircraft.
If by "friendliest", you mean most comfortable, the Boeing 747 in its Upper Deck Lounge configuration has the widest aisles, most leg room, and most comfortable seating. First class in a 747 is the equal or better of any existing passenger aircraft.
Any airplane that the president flies on is called Air Force One. Most often it is a Boeing 747.
A "freighter" aircraft is any plane designed to carry cargo rather than passengers. You can generally recognize a freight aircraft by the presence of double doors allowing a pallet of cargo to be loaded with a forklift. Most civilian airliners are available in a freight configuration, such as the Boeing 747 and Lockheed L-1011. The military generally purchases specially designed aircraft with loading ramps such as the C-130 Hercules or the C-5A Galaxy.
The two biggest manufacturers of aircraft are Airbus and Boeing. You will likely be flying in one of these aircraft on any trip over 200 miles. Other popular aircraft companies for General Aviation aircraft are Cessna and Piper.
The number of wheels on any aircraft will vary depending on the maximum take off mass (MTOM) of the aircraft. A Boeing 737 for example has 1 nose wheel, 2 left main wheels as well as 2 right main wheels (5 in total).
It is extremely unlikely that any airplane will crash. Any airplane that crashes just gets overtelevised by the news channels. Think about this... Theres over 5,000 car crashes in America, EVERY MINUTE. In 2008, there were only about 8 MAJOR aircraft incidents. The aircraft crashes/breakdowns, just get more attention because theres more than 2 or 4 people in the area.