It is still too soon to predict how this will all pan out. It will either be contained or not. From decades of frequent long distance flying I can vouch for the fact that aircraft and airports are guaranteed hot spots of infection.(even if it is just the common cold).I am sure it all accelerated when smoking on aircraft was banned. No need to change the air so much so saving fuel. Plus modern aircraft recirculate 50% of the air so infection is spread everywhere.
Plenty of links available from a general search of cabin air quality for the non believers to pursue.
For me flying is a no no until the epidemiology of this particular horseman is better understood and quantified.
Studies of TB transmissability on aircraft show a very low incidence but the data quality is not the greatest.(according to the Eurosurveillance journal) THe European Centre for Disease Prevention and Control quotes
"The transmission of influenza viruses, for example, is facilitated in closed/semi-closed settings through direct person-to-person contact or from contaminated surfaces. At the beginning of the influenza A(H1N1) pandemic in 2009, air travel was the cause of the introduction of this new virus into countries not primarily affected, and aeroplanes are likely to be a major vector when the next pandemic occurs. The outbreak of SARS in 2003, and influenza A(H1N1) in 2009, illustrated how infectious diseases can suddenly appear, spread and even threaten the health, economy and social lives of citizens in countries that are not or not yet directly affected by the epidemic itself." They issue a series of guidelines for specific threats.

I find it surprising that many studies just track passengers 5 rows either side of a carrier instead of everyone. What is the difference between recirulating air and circulating people? That 5 row cut off seems inexplicable to me. There seems little point in carrying out a survey if most of the passenger manifest is ignored. It skews the derived data set and makes it totally erroneus, and potentially seriously understates the risk.
But the WHO says there is lttle risk because in most aircraft The recirculated air is usually passed through high-efficiency particulate air filters, of the type used in hospital operating theatres and intensive care units, which trap dust particles, bacteria, fungi and viruses.
Once again who to believe? My belief is the WHO is massaging the feel good factor. I do not believe a word of it. Flying poses a risk that has yet to be quantified as far as airbourne pathogens are concerned.
The containment does not seem too successful thus far.