Is the usage of scales (modes) in jazz music common practice?

Question

A friend of mine told me that the usage of scales or modes in jazz music is not common. Even I heard myself in a Miles Davis interview that jazz is a tradition. So here are two questions basically: Is it common practice to use scales (modes) for jazz improvisation? Was is practiced back in the swing era, unlike the modal jazz "era"?

Answer 1

Modes weren't vastly used in jazz before the modal era, starting in the late '50s. Before then, the vast majority of jazz was tonal. The popularization of the use of modes came from the "chord-scale" theory, derived from George Russell's Lydian Chromatic Concept of Tonal Organization, and popularized by schools like Berklee. However, this is not how the majority of jazz musicians approach improvisation even today, and certainly not before the '60s. Approaching tonal music in a modal way can be interesting, but it's not the mainstream.