Near the opening of the film, the pilot and his co-pilot are looking downward through binoculars at the animals below. The next shot shows their "view through the binoculars", but the shots of wild animals are all photographed horizontally, by a photographer on the ground. Moments later, as the plane tries to land, we see a view through their cockpit window, showing the ground at a steep angle (appropriate for looking downward from a plane).
As the plane crashes immediately after the declaration of war, it has a biplane (double-wing) tail. However, a moment later as it crashes into a cliff side, the tail is normal.
Cougars and orangutans are not native to Africa.
When Mike and Bob spot the wreckage, they make an impossible dive towards the ground--and the shadow that is cast on the ground is that of a helicopter, not a plane.