Yes the cylindrical shape of the aeroplanes fuselage requires the windows to be the shape they are!

Unfortunately, people then believe they can observe the earths curvature at around 35,000 feet high which in truth is just ludicrous. If this was true then we would be living on a ball shaped sphere a 1000th the size it is reported by scientific data and known exploration results to be actually 25,000 miles in circumference!

Furthermore, high altitude balloons at 125,000 feet high and without a fish eyed wide angle lens shos the earth as an entirely flat plane at that height. I guess you would really need to go into space and virtually out of low earth orbit to clearly see any real curvature as the planet just is not that damn small to see from a low flying commercial jet period!