That was Corky Fornof doing the flying in the Octopussy clip. Later in the film, the plot reproduced--and Corky re-flew--an event that actually happened to him. He described it to me in amusing detail a few years ago.
En route from South Carolina (maybe North Carolina, don't remember) to DC in the BD-5J, he lost all oil pressure while IFR on top. Shut the engine down and got vectors from ATC to an area where the undercast broke up and an Interstate highway might be visible.
Corky picked up the Interstate, dead-sticked onto it, rolled out and took the (convenient) next exit, rolled down the exit ramp and used the last of his energy to roll into a gas station and up to the pumps, actually setting off the rubber ding-ding hose that signaled a mechanic to come out and service a customer (at least in those days).
Corky told me that when he was about to actually touch down, he came abeam a pickup truck and with hand signals motioned to the driver to back off so that he could land ahead of him. Acting as though this sort of thing happened to him every day, the driver obediently decelerated.