There's no comparison between the two. They're totally different tools. This question is like "what is the advantage of a hammer over a washing machine?"
Fighter jets are good if you want to fight other fighter jets or drop bombs.
Helicopters are good if you want to transport personnel or supplies, observe combat or (if you have an attack helicopter) fight tanks.
Helicopters and jets serve different operational requirements.
Helicopters are better suited for insertion/extraction, ground support, ground attack, SAR, Anti-tank, anti-personnel roles
Jets are better suited for Air Superiority, anti-installation, AWACS, reconnaissance, stealth bombing, long-haul roles
there are more than 250 different kinds of fighter jets.
Around 3000-6000 they have more helicopters than jets
Fighter jets are specialized jet-powered aircraft which are purpose-built for intercepting and destroying other aircraft. They are generally smaller and faster than other types of aircraft.
They have incredibly powerful engines. Most fighter jets are capable of flying faster than the speed of sound. An airplane traveling faster than the speed of sound will be seen before it is heard.
Yes, often. Fighter jets go faster than sound.
In warfare a helicopter is like a sitting duck. The jets will just blow the crap out of 'em cause an air-to-air missle is faster, way faster than a helicopter.
While the question doesn't explicity state which stealth fighter, it's reasonable to assume that all modern day fighter jets have Mach capabilities. This means they are faster than the speed of sound.
The fly on the same principle as any aircraft the difference being they are propelled by jet rather than propeller.
You mean were WWII fighters smaller than today's jets; because "modern fighter planes" are jets. Generally yes, today's JETS are much larger than WWII propeller driven airplanes. But there were exceptions, the US WWII P47 Thunderbolt would be much larger than a MiG 17 Vietnam era jet. The largest US single engine JET was the F105 Thunderchief; you could literally walk underneath an F105 jet, while it's parked on the ground.
That's like asking if a shovel is better than a bandsaw, it all depends on what the pilot is asked to do. A helicopter can land just about anywhere, but it can't hunt down another aeroplane.
beacause the jets suck
It is lightweight and stronger than steel. Steel is really heavy and flying requires light but strong materials.