LAS VEGAS—Planemakers are unveiling new orders and fresh models at the world’s largest business jet show this week as they aim to cash in on a boom in private travel, but executives warn of headwinds due to a capacity crunch. The National Business Aviation Association (NBAA) show returns to an in-person format starting in Las Vegas on Tuesday, testing the strength of demand for jets following the emergence of COVID-19. The show will also shed light on the resilience of the aerospace supply chain, given strained logistics worldwide. Brazil’s Embraer said on Monday morning it signed a deal to sell 100 Phenom 300E planes for more than $1.2 billion at list prices to NetJets, with deliveries starting in 2023. U.S. planemaker Textron Aviation announced updates to the models of two of its Cessna Citation jets, the M2 and XLS. Easing travel restrictions and the lure of private flights have led …