As far as I know, an element of many airplane crashes is fire after landing failure. And it is often known in advance, that the landing may fail. Chances of survival of the passengers and crew could be greater if they would put on them thermoinsulating suits, reflecting infrared, with gas masks to reduce toxic smoke influence (glases of the masks should also reflect infrared). Of course these suits must be fire-proof. The gas filter should contain material with big thermal capacity, so that the air drawn into the lungs would be colder than that surrounding. When breathing out, the material would get colder submitting heat to the air coming out the lungs. I think this is possible to ensure that the air going into the lungs has temperature <60 centigrades.
I know that there is a problem of fitting the suits to different persons, especially children. But I think this is worth. If not, at least gas masks (covering neck) and gloves should be available, because scars on the head, neck and hands are especially obnoxious, and these areas are not covered by own suits of people.
Notice, that the passenger planes are equipped with life-jackets for all passengers, for the event of water landing, which usually does not give survival chances. And in the water this is also important to ensure thermal insulation. The suits could also work as life-jackets if they had foam filling. The suit could be filled with the foam after putting on, if we used foam in spray, like the foam used to repair car tyres (=tires).
I want to point out, that there exists a compound (possibly silver oxide, AgO?), used in modern windows for thermal insulation. Even a very thin layer of it causes significant reduction of the thermal transmission. So a layer of it could be one of layers of such fire-protecting suits.