Senior plc

Senior plc engineers the parts that move air, fuel and heat around an aircraft, and the equivalent parts in trucks, power plants and process industries. The group runs two divisions. Aerospace supplies ducting, bellows, flexible joints, hydraulic tubing, thermal management assemblies and engine fluid systems to airframers and engine makers. Flexonics supplies expansion joints, control bellows, hoses and exhaust gas components to heavy truck, power generation, petrochemical and industrial customers. Head office is in Rickmansworth, north west of London, and the operating businesses sit across North America, Europe, Mexico and Asia, each trading under its own Senior name.

The shape of the company changed at the end of 2025. Senior sold its Aerostructures business, which made precision machined airframe and aero engine components and complex structural assemblies, to Sullivan Street Partners, with completion on 31 December 2025 and a share buyback confirmed alongside it. What is left is a narrower group built around fluid conveyance and thermal management rather than structures. The 2025 results showed Aerospace revenue of 426 million pounds, up 10 percent, with margin improving to 11.4 percent and a book to bill above 1.2, while Flexonics was roughly flat on weak truck markets and leaned on aftermarket mix and restructuring for its margin gains.

Defence content runs through the Aerospace division rather than sitting in a separate unit. Senior businesses make metallic and composite pneumatic ducting, bellows sealed flexible joints, engine exhaust assemblies and hydraulic tubing that end up on military fixed wing aircraft, rotorcraft and the engines that power them, usually as a tier two or tier three supply into the primes. The work is a mix of designed to specification products, where Senior owns the design, and build to print, where it manufactures to a customer drawing. That split matters commercially, because the designed to specification content carries the aftermarket that has been lifting divisional margin.

Flexonics is the part of the group most people outside aerospace meet. Its expansion joints and bellows absorb thermal movement in pipework at refineries, chemical plants and power stations, and its exhaust and emissions components go into medium and heavy diesel engines. The same bellows competence is being pointed at nuclear and solar installations as those markets grow. Senior has around 5,000 employees and reported group revenue of 738.2 million pounds in 2025, spread across operating businesses in a dozen countries that each keep their own works and customer relationships under the Senior name. For a defence buyer the relevant point is narrow and useful. Senior is rarely a prime and almost never a platform owner, but it holds long running qualified positions on engine and airframe fluid systems that are difficult and slow to resource elsewhere, because qualifying a new supplier for a hot section duct or a flight critical hydraulic line takes years of testing that nobody wants to repeat. The guidance going into 2026 reflects that split personality clearly, with management pointing to further Aerospace growth on rising civil build rates and defence demand while flagging softer conditions in parts of Flexonics.