Is there any present technology where a large plane can carry a small plane (or multiple small planes) and drop it midair where the small plane deploys itself? This would be very good from defense point of view, where small fighter jets with limited range could be dropped off by large airplanes with very long range.
If you are talking about externally carrying/deploying other aircraft, this has already been done with the B-52 (albeit for testing purposes) carrying the X-15.
I'm not too sure about having an aircraft drop out of a cargo bay such as the C-130.
On a side note military gliders were used extensively during WW2 and some were capable of carrying light tanks. The gliders were usually towed behind larger bombers to give them the required altitude and speed. They were used because of their wooden construction allowing a stealthy approach due to the reduced radar signature.
Parasite aircraft is a concept that has been considered.
During the era of the zeppelins several countries experimented with launching fighter aircraft from airships, mainly as a way to get the fighter crafts to a relevant altitude while conserving fuel. However none of these projects where realized before the end of WWI.
During WWII soviet used Tupolev TB-3's to carry I-16 dive bombers, a culmination of experiments started during the 1930's. Some of Japan's kamikaze crafts where also launched as parasite aircraft.
In an escort role Germany experimented with parasite craft solutions as a way to bypass the very short operational range of rocket powered fighters, but these experiments where ultimately judged unsuitable.
The extreme range of US strategic bombers in late WWII and early cold war lead US to consider parasite fighters as an escort solution. However these attempts where eventually scrapped in favour of aerial refueling, as this was considered a safer option.
small fighter jets with limited range could be dropped off by large airplanes with very long range
That sounds like a one-way mission.
Some Zeppelins and some US Navy airships did carry small aircraft that could be both launched and, importantly from the pilot's perspective, recovered in mid-air.
However in the modern world, the approach you describe is not used.
If fighters are needed beyond normal operational range of their bases, air forces will either use in-flight refuelling or create a forward operating base nearer the mission target. Aircraft carriers are a popular solution to this requirement, if adequate time is available.
Since your question is about the tech, it very much does exist in a few forms at least for aircraft of varying size.
The Bell X-1 (the plane that broke the sound barrier) was a mid flight deploy from a B-29. This was a result of its low fuel load it could not really get its self off the ground and then have enough fuel to break the sound barrier.
This became common for a lot of the high speed test crafts developed over the years. Up through the X-15 (the fastest thing out there)
The first space shuttle tests were done by flying the shuttle to altitude on a modified 747 and deploying it for an unpowered decent so the tech is there even for large craft.
The more modern Space Ship One also uses this configuration to get it to altitude easier.
The tech is there and has been used over the years. Now to the more realistic question "would you do it" most likely no. As you mentioned there is a case for small limited range planes being deployed at distance but the simpler solution to that is a mid-air refuel. This accomplishes the range extension and allows the plane to get back home. The other option is a drop tank which also extends the range of a plane.
Note: Another kinda of cool solution to the problem was to weld 2 planes into one like the North American F-82 Twin Mustang.
This would be very good from defense point of view, where small fighter jets with limited range could be dropped off by large airplanes with very long range.
Parasite aircraft as a way of increasing the range of fighters has been tried repeatedly, with everything from airships to heavy bombers as the mothership. It turns out to be much harder than it sounds, and has generally been abandoned in favor of dedicated tankers and mid-air refueling.
Germany had some (very) limited success in WWII with the Mistel concept, which is basically the opposite of what you mentioned:
The smaller of two craft was the piloted one, the bigger craft being an explosive-carrying drone -- like a really big glide bomb. The most common combination was a Fw-190 figher/bomber carrying a Ju-88 drone.
where a large plane can carry a small plane (or multiple small planes) and drop it midair where the small plane deploys itself
In addition to those concepts, let us not forget the Goodyear Inflatoplane, which was designed specifically to be dropped from aircraft, inflated, and flown away.
Designed for pilot rescue, the idea of dropping an aircraft in and flying it out was revealed to be ultimately impossible when one considers pilots in a Vietnam jungle.