Yes, there will be a greater force on your knees and hips while running on a treadmill compared to other exercises.
If you want to increase your aerobic fitness, try swimming or water aerobics. They put the least amount of force on your knees and hips. You also get a more complete workout since you are using your arms as well as your legs.
Back on land, you will put less stress on your knees and hips by exercising on a stationary bike or elliptical machine. If you choose the bike, be sure your seat is well positioned. Also, dont ride without any tension on the pedals. You should have enough resistance so that the pedals quickly stop moving if you take your feet off them.
Yoga or Pilates would be a very different path to physical fitness. At first, you likely wont get as much aerobic training as you would from the other exercises mentioned above. But once you get familiar with the moves, you can.
If running is your passion, you will put less stress on your knees and hips by running on a real track rather than a treadmill.