Small Aircraft
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor
Flight Crew Last 90 Days 40; Flight Crew Total 27000; Flight Crew Type 200
Workload; Situational Awareness; Physiological - Other; Communication Breakdown
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action
Environment - Non Weather Related; Human Factors; Staffing
Tower arranged for VFR flight following with ZZZ Departure; transponder code XXXX and a climb to 5;500 feet. I set my altitude alert selector to 5;500 feet. Airborne; I establish contact with ZZZ Departure of my departing altitude and climbing altitude of 5;500 feet. ZZZ cleared me on course to my destination and acknowledge and confirmed my climbing altitude. Shortly thereafter he handed me off to ZZZ1. It was extremely busy and congested; I had to wait several moments before I could establish contact with ATC. My initial contact I stated my departing altitude and climbing to 4;500 feet and not 5;500 feet; ATC did not inform me to notify them of any altitude changes. (realizing my previous transmission with ZZZ Departure I indicated that my cruising altitude would be 5;500 feet which they acknowledged). I stated an incorrect (previously stated to ZZZ Departure climbing to 5;500 feet) altitude that I was climbing to. I immediately tried to correct my climbing altitude with ATC while slowing my climb at approximately 4;800 feet. However; due to radio congestion this took several moments to advise ATC that I was climbing to 5;500 and not 4;500 feet. Due to radio congestion ATC did not receive my correction. ATC was also a little distorted in their communications; later on Controller advised all that could've been possibly due to wearing a COVID mask and [being] shorthanded. ATC informed me of traffic at 5;000 feet on my right side. ATC gave that IFR traffic a turn to the right and shortly thereafter give me a turn to the left. I did not see the traffic visually however I had them on my traffic avoidance system. Once clear of traffic I was given clearance to destinations.
GA pilot reported the ATC Controller was busy; rushed and hard to understand possibly due to speaking through a face mask and the facility being short staffed.