Many of the world's airlines are making ongoing improvements to their onboard products in response to various economic and competitive pressures. But resulting demand for interior products such as seats is placing a growing strain on the relatively few manufacturers, resulting in new business opportunities for smaller, upstart providers, sources say.

Lufthansa has retired its last Boeing 737s after it helped launch the ubiquitous short-haul twinjet during the 1960s and became its first operator 48 years ago.

European airlines have over the last decade been extremely active in the fuel-hedging market, seeking to lock in a US dollar cost item against revenues often in weaker currencies.

Even before the headlines and immediate outlook in Europe came to be dominated by the fallout from the UK's June referendum vote to leave the European Union, there were concerns around whether airline profits in the region would continue to advance at their current pace amid pressured yields.

The German philosopher Friedrich Nietzsche famously said that which does not kill us makes us stronger , which seems a good epithet for the recent experience of Brussels Airlines.