On ordinary commercial aircraft there are none.
Probably around 3 million aircraft
how many commercial airliners are there in the world
It depends on whether you are walking, cycling, driving, flying in a commercial aircraft, combat aircraft or rocket!
Many commercial aircraft are owned by the airline, which would include the jet engines. A substantial fraction of commercial aircraft are owned by aircraft leasing companies, and leased to the airlines; in this case, the leasing company would own the engines.
There are no ashtrays on aircraft. Smoking has been forbidden for many years.
There are 104,322 commercial pilots in the U.S. and 152,933 airline transport pilots in the U.S. as of 2014. A commercial pilot license (CPL), is a qualification that permits the pilot of an aircraft to be paid for his/her work. The Airline Transport Pilot (ATP) certificate is the highest level of aircraft pilot licence and authorizes the pilot to be a pilot on scheduled air carrier's aircraft (commercial airliners).
About 250,000 aircraft not counting commercial, military or government owned. It is difficult to separate those rented or leased back.
The approximate number is 31,850 based on current published fleet numbers of commercial carriers.
about 1-2 years
7
25, 200