Flight Crew Multiengine; Flight Crew Commercial; Flight Crew Instrument
Flight Crew Last 90 Days 40; Flight Crew Total 5361; Flight Crew Type 1482
Communication Breakdown
ATC Issue All Types; Airspace Violation All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural FAR
General None Reported / Taken
Procedure; Human Factors; Staffing; Environment - Non Weather Related
While in contact with ATC and cleared to descend at pilot's discretion I was told to contact ZZZ Tower. I was also told to avoid ZZZ1 airspace which I did. I was not told to avoid the ZZZ airspace. After numerous attempts to get through to ZZZ Tower contact was made. The Tower operator was extremely busy because the Tower was short on staff. This airport was doing a lot of training flights and was very busy. The Tower operator was handling both Ground Control and Tower operations. After finally making contact with the Tower; the Tower operator got upset because I entered his Class D airspace. I thought I was handed off by Approach Control to ZZZ Tower. I don't know if I was handed off by  Approach to ZZZ Tower; or if the Tower operator was to busy to realize what was happening.In the future I will make sure that before I enter controlled airspace I will be in contact with the person controlling that airspace and not depend on being handed off by another Controller. Even though I realize that I need to be more diligent about controlled airspace; I believe that because the Tower operator was so overworked is what really caused the problem. If the Tower operator was not doing Ground Control and Tower Control at the same time in an extremely busy facility radio contact could have been made much sooner and this would have never happened. I would suggest that in the future if the Tower is short on staff; the number of training operations be reduced so as to not overload the Tower operator.
Pilot reported an alleged airspace violation while being under flight following and handed off to a Tower by Approach Control.  Reportedly; Tower Controller was working numerous frequencies/positions and advised pilot that he had violated the Class Delta airspace.