The barking mad plan to build a tinminal in a cul-de-sac! I fondly remember the then Airport Director barking at me for my cynicism!
The original plan was of course for an additional tunnel to the north that would have exited along Frank Lester Way. That was design engineered out of the plans for financial reasons. In effect, a circular one way system.
Probably designed out as it was a rubbish idea. An additional tunnel would put traffic back on local roads as was the original route back in the 80's. The whole idea of New Airport Way and Airport Way was to take traffic way from local roads and housing estates.