Although they may sound the same, there is a big difference between direct and nonstop flights. Knowing the difference can save you a lot of time and aggravation when you travel.
Direct flights can make stops along the way to your final destination. This means you might stop somewhere to drop off some passengers and take on some new ones. The flight number will stay the same and you will be allowed to stay on board the aircraft while this happens. But it takes time to descend and land an airplane, taxi to the gate, exchange passengers. Add in more time to taxi back to the runway and takeoff and direct flights can waste a lot of time if you are trying to get somewhere in a hurry.
Nonstop flights are the point to point flights that do not stop anywhere in between. These flights are the quickest way to get between any two cities. Nonstop flights save you the most time and can make your whole travel experience seem easier. The only drawback to nonstop flights is that they are usually more expensive because there is greater demand.