Is the APU on entire flight?

Excuse me, could you please clarify what you mean by "APU on entire flight"? Are you referring to the Auxiliary Power Unit (APU) that's typically used to provide power to an aircraft's electrical systems, both on the ground and in-flight, in the event of an emergency or during specific operational phases? If so, it's worth noting that the APU is not typically used to power the aircraft during the entire flight, as it's primarily designed as a backup system. Instead, the aircraft's engines typically provide the necessary power for in-flight operations. Could you please elaborate on your question so I can provide a more accurate answer?