Airplanes should be equiped with floaters filled with air under the plane so that the plane can float in sea.. Then you must know that water and the sea is a perfect landingspot for a plane in emergency. So as a pilot always fly above water and flat land, avoid mountains and cities and dont fly over those, cuz a crashlanding in mountains and cities is lethal for everyone onboard. Waterplanes are safest of all, fix the wheels under the floaters, the with air filled barrels and when emergency the plane can simply land on water and not sink. And then everyone is saved, so always fly over water or flatland..
Make the bottom of the plane flat
A flat bottom rests more on the air, it glides over the air i mean while it is best shaped for creating more floating forces. If you make the hull underside round then that falls more then a gliding flat bottom..
Make smaller planes
Smaller planes crash less fast cuz of a better control of it. A huge plane like a 747 cant roll that far to the left or right, cuz too much roll and it drops outa da sky. Also smaller planes feel safer, while its maybe a little more expensive, but safer and that counts more, people wanna pay for that so they will choose all for the more expensive safer planes, so you dont loose any more on more costs for more smaller planes..
Parachutes or kinda containers for 10 persons aboard with a huge parachute
In the back of a small airplane for 50 people are 10 containers in the back that are fireproof, those cant burn in a fire, those have 5 parachutes attached to it and only 1 is needed for safe landing. So the other 4 are reserve parachutes.. The container with the 10 people in can drop in the ocean and it will remain floating. The containers are quickly accessable and are tossed out the rear end of the plane, or maybe else, something else. Safety first..