Could the airplane have been invented before 1900?


Need either super light and strong material, or internal combustion engine.

The later is easier to come by at ~1700s, so maybe in era where crude oil is discovered earlier and used as widespread engine fuel, internet combustion engine would be discovered earlier and there will be something light and powerful enough to power some sort of airplanes during 1750s
The pulsejet engine was claimed to have been invented in the 1860s. It’s much simpler than the internal combustion engine. So no reason it can’t power a Wright Flyer type aircraft during the Gilded Age.
The Wright Flyer first flew in 1903 but it probably could have been built 10 - 20 years earlier if some ROB were to provide a sufficiently talented engineer with the design drawings and the funding. Light weight reciprocating engines start to become commercially available in the late 1870s. At that point the tech-base required to build a Wright Flyer is available, it's the knowledge and understanding of aerodynamic principles that's lacking. Remember that the Wrights (and others) had been experimenting with various glider configurations for close to a decade before hitting upon the one they used.
Steam engined Airplanes maybe with additional Baloons on them ?

John Stringfellow got a model aeroplane powered by a lightweight steam engine to fly short distances in 1848. Plans to scale it up enough to carry a man seem to have been stymied more by lack of funding than technology, solve that and you may be able to do something. Earlier than this is going to be a real challenge though.
Pushing bicycle and motorcycle technology development faster, combine these with more glider research earlier and it could well happen a few years earlier, late 1890s perhaps.


As others have noted, aircraft development required a combinational set of new technologies. As it happened, it's possible to see powered aircraft within a range of say +/- 20 years, depending on varying rates of applied technologies.
Now, that is a thought... imagine the first planes being built, after the first World War....