Aberdeen Airport has been rated the worst in Scotland for the fourth year in a row in the latest Which? survey.
Passengers complained of a lack of seating, long waits at baggage reclaim and the limited range of shops and food outlets.
Airport bosses said the survey was carried out in the midst of its £20 million terminal transformation project, with new retail facilities and an improved security search area opening since then.
Aberdeen received a customer satisfaction score of 49% while Edinburgh Airport – Scotland’s largest – scored 59%.
It ranked fourth best in the UK when compared to other high-capacity airports, after Heathrow Terminal 5, Birmingham and Heathrow Terminal 2.
Inverness earned the highest customer score of the four Scottish airports included in the Which? survey at 68%.
Also in the smaller airport category, Glasgow received 63%, with customers praising their experience as “seamless” and “quick”.
The most common complaint across most airports was charges for picking up and dropping off passengers, described by some as a “money-grabbing exercise”.
An Aberdeen Airport spokeswoman said: “We’re dedicated to improving the airport experience for our passengers, and with this in mind we have upgraded our international and domestic baggage reclaim facilities, as well as new immigration and arrivals areas.
“The feedback we’ve received from passengers has been overwhelmingly positive and are looking forward to opening some of the elements of the next phase of our terminal project in September.
“We are aiming to have completed the project by autumn 2019, which will have increased the size of the terminal by 50%, with 90% of the entire airport transformed.”
Edinburgh Airport said it was good to be ranked “at the top end of the scale”.
A spokesman said: “Aviation is a team game and there are many different partners involved in this Team Edinburgh approach which is why we continue to work with the on-site baggage handlers on improvement while drop-off fees are reinvested in the airport infrastructure.
“We are also one of the only major UK airports to offer a free pick-up and drop-off area, something we are committed to maintaining.”
Glasgow Airport said it worked hard to ensure customers have pleasant journeys and the positive feedback was “welcome news”.
Which? travel editor Rory Boland said: “With new routes to and from Scotland launching all the time, passengers have an increasing choice over not just who they fly with but where they fly from.
It’s clear that some airports will need to improve or risk people taking their business elsewhere.”
The survey was carried out between April and May and recorded 11,265 Which? member experiences of UK airports used in the past year, including 777 in Scotland.