So here I am, six miles up, somewhere over Nor th Afr ica en route to a site inspection of our latest hospital project.
It's a great flight: after long delays the air crew have got it together and now I can enjoy blue skies, a whisky on the table, and great in-flight music and entertainment.
Having rejected the movie Babe , I am happily alternating between classical, jazz and a wonderful series of comedians (channels 4, 7 and 12 respectively) on my newly acquired headset.
But, while gently settled into soporific mood, our pilot, Captain Railton, has just rudely interrupted my pleasure with flight news. You know the stuff: weather, time, this and that - and then, to my surprise, an interesting defence over ecological damage. Airline companies are obviously getting very touchy!
Apparently, on this 'fly-by-wire' A300 single-class airbus flight, we will burn 35 tonnes of fuel. The captain says we took off weighing 171 tonnes, yet down to ear th we w i l l go in about three hours' time weighing only 136 tonnes.
The vegetarian leftie sitting next to me, who in common with all thinking people is of course jolted into selfcriticism by this account, is quickly reassured to learn from our captain that if instead all 304 of us passengers were to travel four to a car to Gambia, we would use exactly the same amount of fuel (35 tonnes! ) at an average speed of 44 mph - not the 550 mph at which we are currently cruising up here!
So, what do you know, I feel great now. This is OK: I'm on a 'green' trip.
Indeed, we're being friendly to those nomadic tribes below by avoiding the traffic congestion that our cars would cause by hacking it over the Sahara.
Another whisky: I have never before felt so good about me and the ozone layer.
But hold on - it's not like that, is it?
Here I am, surrounded by our 'type' (the middle-class European securing a good package deal) - except I'm going to work - and it's quite simple, we don't have to make this trip - none of us. We cou ld have a l l stayed at home to work or play.
Don't kid me - it's a crazy proposal that we would all drive to and from Gatwick to Gambia instead of flying.
Can you imagine us agreeing which cars to share? Half this crowd would want Mercs, Jags and BMWs at 25 miles and less to the gallon, and some would not share cars, while others would go entirely alone.
This analogy is daft: I simply can't imagine 90-odd cars setting off to Gambia for a 10-day break - and that's the point.
We have choice and privilege, we enjoy exclusive benefits which we lap up and protect, and we should not pretend otherwise: raining neat paraffin exhaust vapours over our nomadic friends below does no one any favours.
So, it's a great flight and I'm enjoying a pleasure that previous generations - since time began - had never imagined.
However, the promotion of unnecessary journeys - whether longhaul like this, or merely a quick errand in the car back home - must increasingly be seen for what they are: an enormous threat to susta inab le living, the consequences of which are now all too clear to everybody.