Bill Gates investments are Cascade Investments. He bought into Signature Aviation LLC, largest operator of private jet airports.
https://www.wsj.com/story/photos-inside-bill-gatess-net-worth-theres-much-more-than-microsoft-8a3b102b
Signature Aviation is looking for buyers on website.
https://www.signatureaviation.com/investors/possible-offers-for-signature-aviation
Recommended cash offer (the “Consortium Offer”) by Brown Bidco Limited, a newly formed company to be indirectly owned by joint offerors (i) funds advised by Blackstone Infrastructure Advisors L.L.C. and funds advised by Blackstone Core Equity Management Associates L.L.C., (ii) Global Infrastructure Management, LLC and its affiliates and (iii) Cascade Investment, L.L.C. (the “Consortium”) and other possible offers (the “Possible Offers”) for Signature Aviation plc (“Signature Aviation”)
Signature aviation owns PRIVATE airports.