Maurice Andre uses long tones !
By that I don't mean "TigerLewis - long tones" (playing different tones in one breath).
The first time when he played here in Norway, autumn 1980, with Oslo Philharmonic Orch., I listened to him warming up. I guess he also was testing the acoustics in the concert hall, but still it was long tones (one single note, then pausing, then another single note).
BTW, another great classical cat, Tim. Dokshitzer, has long tone exercises
in his trumpet-book.
(In chapter II, Voclises, Long notes).
More info on that, at my webpage:
Tim. also advocates playing sustained long notes with dynamics (pp -
ff - pp, crescendo, decrescendo).
Ole Jorgen Utnes "Oulee the Gentle Viking"