Plane landing into a tunnel Typical action movies cliché is landing a plane in a tunnel or even a flight in a tunnel. Let's drop any doubts about supreme heroic piloting skills of the characters etc. and focus on aerodynamics.
Would the effect of boundary layer flows in the aircraft vicinity due to the tunnel walls destroy the possibility to fly? It would certainly change the turbulent length scales range.
In fact, how much of "free and undisturbed" field is necessary around a plane? (Rough estimation is ok.)
 A: Flying in the tunnel is actually physically much more easier and economical than flying in air. 
Any flying object will profit from following benefits;
- Positive ground effect to the tunnel floor. (adds lift)
- Negative ground effect to the tunnel roof. (adds lift)
- wingtip vortices are unable to form effectively due to the obstruction of the ground. (lower drag, increased speed and lift)
All this behaviour is explained if you study ground effect. 
This all means, that the stall speed is remarkably lower than expected, and thus it even might be possible to fly some realistic speeds in the tunnel. Ie. Cessna 172 has a Stall speed of less than 90 km/h. It's wingspan is 11 m. 
Considering typical 2-lane tunnel profile width of 11.5 -12 m this is really thight, but possible. Single rail tunnel is not possible, as they have typically 8-9 m profile. 
Any 3-lane road tunnel is completely realistic. 
Most of the roadtunnels are build some 5 m high, so flying in the middle makes the wingspan hight-above-ground -ratio to 2.5 m/ 11 m ~ 1/4, which increases thrust 15% in single ground effect.
Considering all aspects it might be realistic to estimate that the stall speed might be reduced to as low as 60 km/h (30%)
This concludes, that it might be even possible to fly in a 2-lane roadtunnel, but it certainly is realistic to fly in 3-lane roadtunnel with a cessna 172.
Theretically it could be possible to fly in some railtunnel with Helicopter, ie. with Robinson R-22, which has a 7.67 m rotordiameter. In reality the tunnel is full of technology, and doesn't provide much more space than the train needs. 
