European aircraft maker Airbus made a splash on the first day of the Paris Air Show with the announcement of the biggest-ever order for civil aircraft, as the French president joined a big crowd for the event's return after a four-year Covid hiatus.

The 500-plane deal with low-cost Indian carrier IndiGo kicked off what organisers have billed as the "recovery airshow" after the coronavirus ravaged the sector and the biennial trade fair was cancelled in 2021.

Fighter jets and civilian aircraft streaked across the sky while besuited and uniformed delegations, including Ukrainian military officials and President Emmanuel Macron, toured the stands.

This year's airshow has a new focus on defence following Russia's invasion of Ukraine, along with the industry's efforts to reduce its carbon footprint, with French President Emmanuel Macron arriving in a helicopter partly using sustainable aviation fuel (SAF).

Macron called for "restraint" to protect the environment but said measures for aviation should be "reasonable" rather than "punitive", adding that the world shouldn't "give up on growth". 

Huge traffic jams around Le Bourget airport outside Paris were testament to the interest in this year's show, as aircraft makers field hundreds of orders and airlines brace for a near-record number of passengers this year.

The Ukraine conflict has also prompted countries to step up military spending, which could benefit aerospace defence firms.

While Russia has been excluded from the event, Ukrainian military officials toured the huge exhibition space at Paris-Le Bourget airport, some taking photos of missiles on display.

There were star turns for the Rafale fighter made by France's Dassault and the American F-35 jet, with hundreds of visitors turning their phone cameras to the skies and some plugging their ears against the deafening flypasts.

Le Bourget offers a forum to announce deals with some 2,500 firms lining up to show off their latest planes, drones, helicopters and prototypes such as flying taxis.

With 125,000 square metres of exhibition space -- the equivalent of nearly 18 soccer pitches -- around 320,000 visitors are expected during the week-long event.

"Passion for the air hasn't disappeared, that's good news," said Bertrand Godinot, Easyjet's Belgium and France director.

- Big deals -

Along with the Farnborough airshow in England, which takes place in even numbered years, Le Bourget is a key sales event for the civil and defence industries.

Airbus and rival Boeing compete fiercely in announcing orders for aircraft running into the billions of dollars.

Monday's IndiGo-Airbus deal covers A320 family planes at a list price of $55 billion.

Although closely-held actual sale prices are usually lower, it marks the largest ever civil aviation order by volume, hailed by Airbus chief executive Guillaume Faury as "an enormous milestone".

Airbus and Boeing are also battling to solidify supply chains as they increase production to meet growing demand.

At least 158 planes, helicopters and drones will be on display, from the latest long-haul commercial jets to the F-35 stealth fighter.

The United States has a strong presence with 425 exhibitors, while firms from 46 other nations are present.

China, which lifted Covid restrictions only at the beginning of this year, is also represented. 

However, Beijing is not displaying its first homegrown medium-haul passenger jet, the C919, built to compete with the Airbus A320neo and Boeing 737 MAX.

- Flying taxis -

The airshow also hopes to open a window into the future as projects for flying taxis and other vertical takeoff aircraft abound.

Several prototypes will be on display as part of a "Paris Air Mobility" exhibition to showcase the latest innovations that developers hope will change how people travel.

Engine maker Safran announced early Monday that it would open four production lines in France and Britain making electric motors for small planes.

For his part, Macron arrived aboard Airbus' latest helicopter, the H160, in a flight fuelled with 30 percent SAF before visiting the European group's stand laying out its net-zero-by-2050 plan.

Macron had on Friday announced $2.2 billion to help develop technologies to reduce aircraft emissions.

Air travel accounts for nearly three percent of global CO2 emissions but serves only a small minority of the world's population.

With the industry targeting net zero emissions by mid-century, firms are turbocharging efforts to achieve it.

The initial focus is on SAF, made from sources such as municipal waste, leftovers from the agricultural and forestry industry, crops and plants, and even hydrogen.

But companies are also working to develop battery- and hydrogen-powered aircraft.

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