And on the BA London to Glasgow Shuttle I never saw the pay on board, though the cabin crew did come down the cabin collecting all the tickets.

To save me adulterating this Eastern discussion with stories about the comparable British Airways one, though I am sure some issues afflicted both, here's a link to a discussion, including by a number of the actual participants, from a few years ago in another PPlace (including someone who remembered flying on the Eastern one, in a Super Connie no less, and paid on the plane) :

British Airways Shuttle dates - PPRuNe Forums