In the original run of 100 Telecaster bodies and 409 Stratocaster bodies sent to Fender in 1993 after being fabricated by Spruce Hill Music in Minnesota, the skin of the bodies is 1/16" sheet aluminum mounted to an inner framework of... 1/4" X 1" aluminum bars, if I remember right (mine's all put together right now). There are a few larger plates welded where the bridge attaches, and one big solid chunk which is the neck block. I'm sure the Strat has some differing ways to support the whole tremolo business. There's a kinda undetermined amount of that original run that fell off the truck or wasn't sent for some reason; the Tele I have has some faint little buffing marks where particles got caught and the metal was buffed down around them, you can barely see them but still... I do know Fender originally told Spruce Hill they didn't care about the overage and then called back to claim? Seize? Destroy? them but they'd already scooted.
Since then, there have been all sorts of differing versions of Telecaster-and-other shaped aluminum guitars, made in every way possible including machining them down from a single billet! And the Velano guitar actually predated them, as did both the Kramer and Travis Bean aluminum-necked models. Mine is definitely light in weight, probably around the body weight of a very light little SG or LP Jr..