Theo is a business correspondent.
It has been a long time since. This week, a sleepy airfield in Hampshire will once again host the biggest names in the global defence industry.
More than 80,000 people are expected to attend the Farnborough Airshow, which is being held for the first time in 4 years.
The flying displays will be loud and colorful, with the Red Arrows, South Korea's Black Eagles display team, an RAF Typhoon and a US Air Force F-35 all dropping by.
The war in Ukraine has changed the outlook for the defence industry, while the Covid Pandemic has had a significant impact on commercial aviation.
This year's event gives businesses an opportunity to assess how they are doing in a very different world.
Things haven't changed.
The pressure to cut emissions and become less damaging to the environment is as strong as ever, and "sustainability" is likely to be one of the main buzzwords.
Normally, the Salon du Bourget in Paris is the most prestigious industry gathering of the year.
In the shadow of billions of pounds worth of state-of-the-art machinery, executives in sharp suits mingle with military types in gold braid and dark glasses.
It was used as an opportunity for showmanship. All forecasts indicated that the airline sector would continue to grow.
The good times were cut short by the outbreak. Airlines weren't flying in a lot of areas. Factory production slowed as aircraft were grounded.
The show's people are convinced that confidence is coming back.
The world has not flown a lot for the past three years, according to Kevin Craven, chief executive of the UK.
The proof that the industry has used the time well and is looking forward to the future is symbolic.
The focus will inevitably be on the two giants of the commercial sector. The US manufacturer has had the most difficulty over the past few years.
The plane will be at the show. The design that was involved in two fatal crashes in Ethiopia and Indonesia is related to the newest version of the plane.
Boeing is hoping that the plane, a highly efficient long range model, will allow it to compete with the A321neo and help rehabilitate the Max brand.
There are problems that need to be fixed. The aircraft won't be certified by regulators before the end of the year. New safety rules will apply if it is not.
They would force Boeing to make changes to the flight deck, meaning that pilots coming from other versions of the plane would need more training, raising costs for airlines, and making the plane less attractive.
There is a risk that the programme could be canceled if the company is not granted a waivers from the new rules.
The company has yet to resume deliveries of its flagship product. There have been a number of production and quality control problems that have halted these for more than a year.
Boeing needs a good show to build confidence and appease disgruntled investors.
The company is going into the show in a positive frame of mind.
Demand for passenger air traffic will increase by 3.6% a year for the next two decades, and that pressure to reduce emissions will increase demand for fuel- efficient aircraft, according to the company.
The A320neo, A350 and A321XLR are some of the planes it believes will benefit.
Cutting carbon emissions is likely to be one of the main topics of discussion as executives swelter in what is forecast to be a very un- British heatwave.
The challenge of decarbonisation was brought to the forefront by Covid as he had almost no flights and therefore no emissions.
As travel returns, so do the emissions associated with it.
There's going to be a lot of discussion at the show about how to reach the goal of net zero by the year 2050.
Future plans for a new generation of hydrogen-powered planes are likely to be discussed in such discussions.
Several companies will be talking about their plans for electric air taxis.
Change is taking place in the defence sector. National defence budgets have been boosted by the conflict in Ukraine.
"We were already seeing this pivot away from counter-insurgency capabilities to much more focus on near-peer adversaries, and the capabilities you need in those circumstances."
I think we're going to see a lot of discussions between government military representatives and the different defence contractors that are at the show, checking out products and talking about potential deals...
Billions of dollars are what deals are all about.