a. Estimate how many commercial passengerjets are in the entire U.S. fleet. Provide some approximate quantitative reasoning to derive your answer don't just pull a guess out of thin air and or go to google (you'll only get credit if you show your assumptions to arrive at a reasonable estimate). Express your answer as one of the following intervals: 100 101, 10- 102, 102 103, 103 104, 104 105. (10 pts.)