Inflatable structures in boats have proved extremely successful and versatile since they began to find widespread use in the 1930s.
I'm aware that experiments have been made with inflatable wings - very light, delicate structures mainly on human-powered and unmanned aerial vehicles.
On boats, they're used differently: in some cases they form the main structure of the craft itself, in some, the craft has a rigid hull and the rest of the structure is inflatable, but either way, the inflatable sections are very far from delicate.
Experience gained with multiple air cells in inflatable engineering means that it's now possible to build effectively rigid structures, that are extremely tough, reliable and resilient. Their behaviour in failure modes is well-known.
Many large aircraft have built-in air compressors - the engines - that could keep the inflatable structures correctly pressured at all stages of a flight.
Materials science has produced enormous improvements in the longevity and resistance to chemicals/sunlight/temperature ranges of the rubber skins of inflatable structures.
What opportunities are there for designing parts of an aircraft as inflatable structures (perhaps winglets, or undercarriage doors)?
Is there any research or experimentation into more heavy-duty use of inflatable engineering in aircraft?