One of the most obvious and manifest changes in the Western world after the 9/11 terrorist attacks in America was the huge increase in security.
Business travellers were immediately aware of it as queues and therefore time spent at airports increased markedly. Where before the attacks two hours were ample even for international flights, post 9/11 airlines and airport authorities began requiring passengers to arrive three, even four hours before take-off.
It was the negative side of flying which did its share of putting people off travel. Thanks to improved technology, including the wider use of biometrics and smartcards, online check-ins and self service kiosks, the passage through airports has been speeded up without any corresponding loss of security.
But if this balance between essential security and passenger convenience has been redressed, there is another, perhaps even more important balance that needs attention.
This is the balance between passenger information and privacy, between what a host country needs to know about a visitor and what is prying and, possibly most worrying of all, who receives this information and what is done with it.
It is a thorny and extremely complex problem that the Association of Corporate Travel Executives (ACTE) is now - some would say at last - addressing. The EMEA region, following in the footsteps of its US equivalent, has set up a Traveller Security Task Force to study issues such as privacy and passenger security.
The seven-strong group, which will hold its first meeting in September and then meet regularly after that, will first have the job of identifying the most pressing issues and then work out the most appropriate responses.
It will also monitor any proposed legislation by the US, the EU or individual governments and put ACTE's views across to them.
Stan Berteloot, ACTE EMEA regional director, said its job would not only be to monitor proposed new laws but also, more pro-actively, to tell the EU what are the major security concerns of the corporates and their business travellers.
A good example of this was the original proposals from the US regarding what details were needed from individual passengers under its Advance Passenger Information System (APIS). Travellers feared it would lead to long delays while forms were filled in while corporates feared it would lead to fare increases to cover the airlines' administrative work.
Besides a likely negative impact on travel, many others felt this information would be available to too many different US authorities.
Fortunately these original APIS proposals were rejected by the Europeans but a new, slightly less severe version is now in place.
Laudably, Mr Berteloot said the new Task Force would be “very concerned with everything that has to do with data privacy. We want to increase security for the community but we also want to keep an eye on what might violate people's privacy. The right balance has to be found.
“We believe that some requirements might hurt both the industry and civil liberties so we shall be monitoring them and advising on what we would like to see tackled.”
Many of the security measures directed at visitors to America which the US authorities wished to implement after 9/11 are or soon will be in place.
But with terrorists continuing to be a threat and, as Madrid and London will testify, a reality, politicians - not a calling that in general cares much for civil liberties - are likely to seek ever tougher measures to thwart them.
ACTE's new Task Force might just find it has a major job on its hands.