why Boeing 707 planes are no more used now?

Flew nice, especially the newer "advanced" types with series yaw damper -

Up to 189 passengers - there was a version with 219 seats -

CFM-56 engines could have extended their operation for 10 more years -

But only the KC-135 (707 tankers) were re-engined with CFM-56 engines -

Many AWACS (these are 707) are equipped with these engines -

They still are in use in some places. However, it's a very old design, the first flew in the early 50's, and the huge growth in air travel meant that it soon became too small to handle the increased passenger densities on the routes for which it was designed. Stretching the fuselage was not a viable option so Boeing brought out the first twin-aisle airliner - the 747. The first-generation engine technology also rapidly became obsolete in the areas of noise and fuel economy.

The last civil version was produced in 1978 so even the newest is now over 30 years old.

Almost all commercial airplanes eventually become unserviceable. They become too expensive to maintain, they develop structural cracks and metal fatigue that could make them dangerous to fly, spare parts become scarce, and as efficient as they were when they were built, they are no longer as efficient as the newer planes. New safety features, avionics, flight controls, entertainment and other features on newer aircraft are difficult to retrofit into older aircraft, because many of these new features are built into planes when they are first designed and built. If an airplane cannot be brought up to current safety and reliability standards, it can't be used for regular commercial air travel. At least not in the United States. Many other countries have the same kind of regulations as the U.S. There are a lot of old perfectly good aircraft out there that have been flying for decades, but generally speaking, they have very limited operations and are not reliable enough for day-to-day use like a new aircraft is.

Same reason a Ford Prefect or an Austin 7 is not used now.

Better planes have come along

The 707 was small, very noisy, polluting and not particularly efficient by modern standards

First it has 4 jets so it burns more fuel than other planes. It can only hold 148 passengers. It was replaced by the boeing 757. The 757 only has two jets and can carry 247 passengers.

there are still many flying today but they dont make them any more but the actor john travolta has a 707 and flys it regularly he even flew relief supplies to haiti in it

they are, just not in the US/Europe, you go to places like africa, where they can't really afford top of the line aircraft and you're bound to run into a few still going

(though I wouldn't want to fly on them,lol)

Same reason we no longer use the model T Ford. And NO. they were NOT efficient.

Some African countries still use them. Possibly also Iran for the Military.......But I might be thinking of Libya.

they fall out of the sky and kill babies