YOU SAID:

Planes fly very fast at very high altitudes

INTO JAPANESE

飛行機は非常に高度で非常に速く飛ぶ

BACK INTO ENGLISH

Airplanes fly very high, very fast

INTO JAPANESE

飛行機は飛ぶ非常に高い、非常に速い

BACK INTO ENGLISH

Planes are flying very high, very fast

INTO JAPANESE

非常に高い、非常に高速に空を飛んでいる飛行機

BACK INTO ENGLISH

Planes are flying very high, very fast