I'm glad you enjoyed your visit and the new central pier will have seats in its four new pre-boarding zones. The pier currently under construction is illustrated in a video at the below link nearly half way down the right-hand-side of the page that also shows the full extent of the proposed expansion plans of which the pier being built now is the latest phase.
Planning and development ? Bristol Airport
You may well have used the western walkway which is only a few years old but was built under general permitted development not requiring full planning consent, but this meant it could not be used to enhance the floor area of the terminal with such things as seating, apart from a minimal number to cater for people with impaired mobility. Planning consents have since been obtained for the major expansion which means that the 400-metre long western walkway could be upgraded but thus far the airport has chosen not to.
The airport is on a small site as some of the previous posts in recent days have mentioned. The new terminal opened in 2000 was built into the side of a hill which means that incoming passengers enter at ground level from the apron, descend the stairs and leave the terminal still at ground level.
JaffaCake talks of the airport's idiosyncracies and he's undeniably correct. In some ways it's entirely appropriate because Bristol is an idiosyncratic city. The Sunday Times recently decided it's the best city in the UK to live (this sort of thing will always be subjective) and it's certainly one of the country's most economically successful cities. PM Cameron last year said it was the second richest UK city after London but I don't know how he measured that - presumably by GVA or GDP per capita. Yet it sits cheek by jowl alongside some of the most deprived areas in the country with its inner city and huge, sprawling council estates on its edges.
Your Flyer journey would have taken you through the down market suburb of Bedminster (but even that has its jazzy parts) to Bristol's main railway station which is set well away from the central areas - another idiosyncracy.
Bristol Airport like the city whose name it bears can be both infuriating and endearing, often at the same time, which is why some people love both.