The Entertainment Industry comprises of a plethora of businesses, organisations, individuals, venues and premises which have a central purpose to engage or enthral an audience. The central purpose of air travel is to transport passengers or freight from one location to another not to engage or enthral an audience, however aircraft can very easily become objects of entertainment - particulary at organised airshows (which fall within the entertainment industry) as the sole purpose of an airshow is to attract, enthral, and engage an audience using a variety of aircraft.
Watching an aeroplane land from the ground may not hold mass appeal, but to some individuals this spectacle can be most entertaining - which is why at many airports there are viewing areas for this purpose. The aeroplanes that are being viewed are still not a part of the entertainment industry, however as the viewing area has been purposely built with the sole intention of captivating an audience of aircraft enthusiasts, it does indeed fall within the remit of the entertainment industry - as well as of course the airport industry, transport industry and tourism industry.
As a point of fact, the only major difference between the entertainment at an airport viewing area, and the entertainment at an organised airshow is that airshows have aircraft displayed solely for entertainment - at airport viewing areas the entertainment on offer is a by product of the normal function of the aircraft, but as the viewing area is a venue built specifically for the purpose of the enjoyment of aircraft viewing, the viewing area itself is an entertainment venue. The image below was taken at the Manchester Airport viewing area.
If you look hard enough, entertainment can be found in a variety of places - many of which might seem obscure - but if they are engaging and enthralling, their entertainment credentials cannot be denied.