The speech will follow a tour of the Farnborough site where the PM will see examples of the latest plane models, meet with key industry figures and watch a flypast including Spitfires and Red Arrows to signal the start of the event.
"Beyond the order avalanche, manufacturers, suppliers and airlines use the event to haggle over contracts and float ideas for new planes and ventures", Bloomberg adds.
"While Trump has said trade wars are 'good and easy to win, ' aviation experts say American companies like Chicago-based Boeing will take the first hit because most of US aerospace production goes to foreign buyers".
Bloomberg News notes "billions of dollars are at stake as the world's largest planemakers ... duel over orders this week at the Farnborough".
Jet Airways confirmed an order for an additional 75 737 MAX 8s.
Heading into the show, Toulouse, France-based Airbus was closing in on orders totalling $29bn, based on list prices, from two Asian carriers, Malaysia's AirAsia, and StarLux Airlines.
On the civilian side, the air show is expected to confirm demand for narrowbody jets from airlines such as Mexico's VivaAerobus, which is shopping for some 40 Airbuses, and lessors like Goshawk, which ordered 20 A320neo jets on Monday but is also expected to be interested in 737 MAX.
"Let me make one thing clear", Tinseth said.
'But this year fears about the future after Brexit are looming, and for many people will dominate gossip in the plush chalets and meeting rooms. He insists that any failure to agree a good deal on Brexit will hurt the sector.
Sensitive UK choices over worldwide partnerships are also expected to loom large in the defence side of the show.
Boeing's upbeat sales forecast underlined the importance of China to the aircraft industry.
Boeing, fresh from striking a deal with Embraer, will issue its global demand outlook on Tuesday. But could there be a hitch?
Rising oil prices and interest rates, trade tensions and uncertainty over Britain's departure from the European Union all pose a risk to an eight-year boom in civil aviation, which has boosted industry order books and share prices.
The 2018 Farnborough Airshow runs from July 16 to July 22.
Boeing's vice-president of commercial marketing Randy Tinseth told a news briefing that China looked set to overtake the United States as the world's biggest domestic air travel market in 10-15 years.
"Airbus has missed a number of deadlines for deliveries, forcing airline customers to find alternatives, change routes or cancel flights".
And US aircraft leasing company Air Lease Corp announced a commitment to order as many as 78 Boeing single-aisle and wide-body airplanes in a deal valued at $9.6bn at catalogue prices.
Past year was the best for cargo since 2010, with traffic growth more than doubling to 9 percent, three times the growth in capacity.