I'm sorry if this is a little fantastical, but I'm just wondering if this type of maneuver is possible in any way. I understand if this question gets pulled. I'm trying to make a little action-animation-cgi and just wondering if this was ever a last-resort option for maybe two planes, maybe one is a bit larger than the other but maybe similar speeds could be maintained for the one plane that is running out of fuel could latch-on somehow.
The Navy has already done this using airships. Here is a video showing launch and recovery. USS Macon launching a recovering aircraft.
Let me take a stab at the "inside another plane part".
One of the smallest trainer planes is the Cessna 172, with a wingspan of 36'.
One of the biggest cargo planes is the C-5 Galaxy, with an inside diameter of 19'.
So right there, you'd be hard-pressed to find a small plane that could even fit inside a larger plane.
The next problem is airspeed: The C-172 needs to travel at least 40 kts to maintain flight, and this is 40kts relative to the air it is in, so if it were inside the cargohold of a larger plane, it needs to be traveling 40 kts faster than the larger plane. I couldn't find a canonical reference for the C5 Galaxy's minimum speed, but I can estimate it around 140 kts.
This means that on approach to the host-plane, the smaller plane would need to be doing about 180 kts relative to the outside air. That is around the fastest speed the Cessna is capable of; it would need to be in a considerable descent at full power to achieve that speed. The propeller would be turning about 2700 RPM.
On the transition from outside the host to inside the host, the small plane needs to slow its propeller from 180kts (2700 RPM) to only 40 kts(1200 RPM). The propeller needs to slow to landing speed nearly instantaneously, otherwise the fast propeller would accelerate the smaller plane relative to its host.
Essentially, the parasite-plane would need to be in a considerable descent at full power to make an approach speed. Then as it enters the host-plane, it would need to level off and slow its propeller drastically. This seems incredibly risky.
Once you're inside the larger plane, the Cessna has a published landing roll out of about 500 feet. The C-5 Galaxy has a length of around 250 feet. So you'd need some sort of arrester cable system, like found on aircraft carriers.
So, in summary:
- Most big planes are not big enough to fit small planes inside
- Small planes cannot go fast enough to catch up to a big plane's minimum speed.
- The airspeed transition from outside a big plane to inside a big plane is extreme and sudden.
- There isn't a lot of space in a big plane for a landing roll out.
So, I would generally say "No", landing inside a larger plane seems impossible.
Something similar has happened before; see Pardo's Push.
Two F-4 fighters were on a mission over Vietnam when they got hit with anti-aircraft fire. One jet lost too much fuel to be able to make it back to a tanker or air base. The pilot of the other jet, Captain Bob Pardo, used the canopy of his jet to push on the tail hook of the other jet.
This was certainly a "last resort" situation. It slowed their rate of descent just enough for them to fly further back to base. Both pilots bailed out and were rescued, eventually being awarded the Silver Star.