Im using 707-320B ADVs but even before I saw this possible warning I've had them all on fairly short leases. At the moment, they looked to be the best available used option left when I got started late in day one. The profit margin has been rather narrow so I am concerned at what might happen when fuel inevitably spikes; although my load factors have also of course been rather low to start off. I figure once my image improves and I get more passengers, these planes should do just fine for now. If not, I can phase them out completely within four years.