FARNBOROUGH, UK, July 20 (Reuters) - Airlines unveiled aircraft orders as the Farnborough International Airshow opened on Monday, with more expected this week at the British event, one of the world's largest sector gatherings.

Still, industry sources said they expect dealmaking to fall short of expectations of 800 aircraft or more, as Airbus AIR.PA and Boeing BA.N continue to grapple with supply-chain constraints and production bottlenecks.

Below are the key deals so far.

SMBC AVIATION CAPITAL

Boeing and SMBC Aviation Capital announced that the global aviation finance platform and lessor has ordered 100 737 MAX airplanes, including 60 737-10 and 40 737-8 jets.

The 737-10 order represents SMBC Aviation Capital's first purchase for the 737 MAX family's highest-capacity variant.

RIYADH AIR

The Saudi carrier exercised options for 28 Boeing 787 Dreamliners from an order placed in 2023, converting 20 of those aircraft to the larger 787-10 variant.

It also confirmed an order for six Airbus A350-1000 aircraft, increasing its total firm A350-1000 order book to 31 aircraft.

PHILIPPINE AIRLINES

Boeing announced a new order for up to 20 787-10 Dreamliner widebody twinjets from Philippine Airlines, consisting of 15 firm orders and five options, as the pair build on an 80-year relationship.

While Philippine Airlines has a long history of flying Boeing aircraft, including its current 777-300ERs, the carrier has never previously operated Boeing's 787-10 Dreamliner.

OTHER DEALS

Japan's Skymark Airlines has shaken hands with Aviation Capital Group to lease seven Boeing 737 MAX 10 narrowbody twinjets, with deliveries beginning in 2028.

The first Airbus order of the show came in the form of a commitment for two more H135 helicopters from the UK's National Police Air Service, bringing the total fleet renewal programme to nine H135s. Deliveries are expected in 2028.

ENGINE ORDERS

British Airways announced that it has selected Pratt & Whitney GTF engines for up to 63 incoming Airbus A320neo jets: 33 firm orders and 30 options.

Singapore-based lessor BOC Aviation placed its largest-ever engine order, agreeing to purchase and option up to 300 CFM International engines to support its expanding Airbus and Boeing narrow-body fleet.