Part 107 UAS pilot reported making several attempts at obtaining LAANC authorization. After failed attempts to obtain authorization the UAS pilot conducted the flight without it.

Narrative

I was scheduled to fly my Autel Evo II Pro under part 107 on Day 2 at Location A under the assumption that a verbal authorization was given by the Airport Manager at ZZZ. The flight was completed successfully without incident. The reason for my wrongful assumption is as follows.A previous attempt to complete the drone flight in the no-fly zone was initiated via a request made through the FAA DroneZone website. The date of the scheduled flight (Day 0) the authorization request was still under review. I called the ZZZ airport number and left a message with the Airport Manager asking if he had a chance to review the flight request. I did not hear back so the flight was canceled. On Day 1 the Airport Manager returned my call and apologized for not getting back to me as he was away. We discussed the requested drone flight approval; and I mentioned that I could go back on Day 2 to complete the flight. He stated to resubmit the request for approval through the FAA website and he would get it approved and also let the tower know of the flight. I resubmitted the request and saw that it was under review the next day. On Day 2 I noticed that it was still under review. When I arrived at Location A; I called the tower; but it would only go to voice mail. In the initial message upon calling the tower it stated that the hours of operation were from XA:00 am to XB:00 pm. I left a message in the Airport Managers voice mail stating I was on site and commencing the flight as discussed. Upon completion I again called back and stated the flight was completed. On Day 3 I received a call back from the Airport Manager stating that he does not give verbal authorizations and that he never saw the new flight request through the FAA DroneZone site. My errors were as follows. I executed a flight without written authorization and due to the hours of operation at the airport and my conversation with the Airport Manager; I thought the verbal conversation allowed for a legal flight in requested area. This was a unique situation in discussing the flight with authorized personnel; however; my failure was not receiving the written approval in hand. My corrective actions are to never complete a drone flight in a controlled airspace without written approval regardless of any verbal discussions. I do not fault the Airport Manager as he was very accommodating and helpful. The error lies with me in misinterpretation a discussion as authorization to complete the flight.