The majority of firms doubt whether a new runway for the south-east of England will ever be built despite the government giving the go ahead for a third runway at Heathrow.
As many as 73% of businesses questioned for a new CBI survey are not confident that a new runway will ever materialise.
Only 27% of businesses (27%) expect aviation connectivity to improve over this Parliament.
The devolved nations are more positive, with 61% of firms in Scotland and Wales anticipating better connectivity.
Almost half of all firms (46%) expect to lose business if the UK fails to increase the number of flights with emerging markets, rising to 88% for multinational companies.
More than two thirds (70%) of firms see faster road and rail access to the UK’s airports as critical or important, and 59% think the same about more resilient airport infrastructure.
The findings emerged today among the results of a wide-ranging infrastructure study conducted by the CBI with engineering company AECOM.
Delivery of key projects already in the pipeline emerged as the top priority among the 728 firms surveyed.
Investment in the rail network, UK motorways and A roads rank highly, as does delivery of a new runway in the south-east (85%) and the high speed HS2 rail line (80%).
But a significant majority of firms are not optimistic that infrastructure in aviation (74%), energy (73%) and roads (69%) will improve, with only digital bucking the trend (59% of companies expect improvements in this area.
The majority (64%) of firms also feel the UK is unlikely to be more internationally competitive in 2050 than it is now, and 46% are dissatisfied with the current state of their local infrastructure.
AECOM chief executive – civil infrastructure, Europe, Middle East, India & Africa, Richard Robinson, said: “After decades of deferred and delayed decisions, it is hardly surprising that 73% of firms are not confident that a new runway in the south-east will be built.
“But last month’s green light from government for Heathrow will hopefully go some way to restoring confidence. It sends a strong message that the UK is open for business.
“As the country plans for post-Brexit scenarios, it is vital the UK is more outward-facing so it can better compete globally.
“The focus now however must be on accelerating delivery. With nearly half of firms (46%) expecting to see lost business if the UK fails to increase its connectivity with emerging markets, the decision comes not a moment too soon.”
CBI director general Carolyn Fairburn said: “Our message is a simple one: at the end of the day, delivery is what matters. It’s great the government is taking the decisions for our long-term future prosperity, like giving the green light to the new runway at Heathrow, Hinkley Point and improving digital connections.
Businesses also need clear, deliverable timetables for action on major national projects in order for them to act as magnets for investment, growth and jobs.
“If we don’t get spades in the ground on existing plans, it’s clear we could put a major dent in the competitiveness of British business – and the UK itself. This is something we cannot afford do, especially during this period of uncertainty as the UK leaves the EU.”