As Bob implied above, a lot of titanium tubing initially used in bicycle production was aerospace sourced. (Unverified rumor: this was the stuff that didn't pass inspection for aircraft use.) I remember seeing titanium-leg mountain bike forks in the early '90's, but building something that would look right on a road bike would be pretty tough. Even now they are pretty pricey: https://www.ebay.com/i/271143626844?chn=ps