Thomas Cook Group and Tui Travel have both decided to dispose of the majority of their interests in the Airline Group, a shareholder in UK air traffic controller Nats.
Lufthansa and Virgin Atlantic are also selling the majority of their stakes in Airline Group on the same terms.
The combined shareholding being sold to USS represents a non-controlling stake of 49.9%, with each seller retaining a small proportion of their holding.
British Airways, easyJet and Monarch Airlines will retain all of their share and loan note interests in Airline Group.
Tui Travel will sell 87.4% of its shareholding and loan note interests in Airline Group, which holds a 41.9% stake in Nats, to Universities Superannuation Scheme Limited, acting as sole corporate trustee of Universities Superannuation Scheme.
Tui Travel will retain a small shareholding in Airline Group following the deal.
The transaction is expected to be completed in the first quarter of 2014 and is subject to clearance from the European Commission.
Tui Travel chief financial offier Will Waggott said: “Following the merger and subsequent creation of Tui Travel in 2007 our interests in Airline Group were identified as non-core.
“We are pleased to sell the majority of our interests in Airline Group and at a value that exceeds the current carrying value of the investment.”
Thomas Cook Group chief executive Harriet Green said: “I am delighted to report yet more progress in our transformation of Thomas Cook.
“Delivering on our previously announced commitment to realise value from non-core businesses, this sale represents an important milestone in our disposal and debt reduction plans, contributing £38 million towards our target to generate between £100 million and £150 million in gross proceeds by FY15.
“It also enables us to intensify our business focus on the further delivery of our profitable growth strategy, which we look forward to sharing in more detail in our results announcement on November 28.”