As hundreds of thousands watched the Sunderland airshow at the weekend from terra firma, Duncan Leatherdale experienced proceedings thousands of feet up aboard a Second World War flying boat.

MY father is a retired pilot who has flown crop-sprayers in Africa, tourists across Cornwall and science surveys in Antarctica, yet even he was jealous when I told him I was going up in one of the most famous seaplanes of all time.

The Second World War Consolidated PBY Catalina was so successful no other flying boat was made in greater numbers. It completed essential tasks such as anti-submarine warfare, convoy escort and search and rescue missions.

This particular example started its service in the Royal Canadian Air Force, where it served with distinction in Scotland and over the Indian Ocean. It then returned to Ontario, where it was used for mapping and reconnaissance, often spending long spells in the Arctic.

In 1961, its military career ended and it was converted into a water bomber to be used in the battle against forest fires, a role performed across Canada and in France.

The Catalina was then purchased by a group of Malaysian businessmen who wanted to use it for tourism in Zimbabwe, which is when the two gunners’ posts at the rear of the plane were replaced with the large blisters, as the bulbous windows are known. But, due to political upheaval, its time in Zimbabwe was shortlived.

Housed at Duxford Air Museum, in Cambridgeshire, since 2002, the airshow staple is an odd-looking aircraft, with the hull of a boat and two engines placed high above the centre of the fuselage, like large, noisy rabbit ears. Inside, there are several compartments, much like the body parts of an insect.

For take-off and landing, I sat in the compartment behind the cockpit. Behind me was a smaller area above which roared the two propeller engines, then some more seating before the final and most impressive area at the back, where the two large bubble windows maximised the views.

As the engines thundered overhead, revving up and down, I was struck by how beautifully uncomplicated everything was. The emergency exit was fastened with a handle that looked not unlike the one I use to open my windows at home. And all that stood between me, in the stifling belly of the plane, and the air outside was a glorified car boot.

Where was the large sealed door you see on a commercial airliner?

Flying commercially you almost forget you are thousands of feet up the air. In the Catalina, you feel every jolt and rock, and standing in the blisters, you feel as if you are on a platform floating across the landscape.

We climbed to 10,000ft and, within two minutes, were above Newcastle, The Sage glittering like some large slug basking on the riverside, before heading out over Sunderland, where we dropped to 500ft for views of the crowded Seaburn beaches.

As the crowds looked at us with interest, we looked back in wonderment.

After 15 minutes or so I must confess to feeling a bit queasy, a combination of the stifling heat that had caused rivers of sweat to rundown the face of the Tyne Tees cameraman, and the constant rocking of the craft.

But there was one moment of pure joy as we flew towards the beaches. Looking down, I could see traffic jams snaking along the roads, yet here we were soaring serenely, if not a tad shakily, over their heads.

AFTERWARDS, as we stood cooling down in the shade of the long wings, one of the captains, a retired commercial airline pilot, told me that the plane had been in the thick of it during the war.

In one instance it had been sent off the coast of Norfolk to rescue sailors from a sunken ship.

But, as it made to take off from the water after the rescue, the Germans shot it down.

Today, the crew would not dare land it on the sea, not for the fear of enemy fire, but for the fear of rust.

Volunteer Chris Bailey explained that now the craft only lands on fresh water, the salt in sea water would start disintegrating it.

She said: “It’s not the bits of rust you can see that you worry about, but the bits you can’t.”

The plane is owned by a group of 20 shareholders.

Two shares are up for grabs at £17,000 each, plus £150-a-month for maintenance costs.

While that might be out of my reach, I got to experience something that made other wouldbe flyers – and even my father – envious.

For, as much as it was a thrill for the thousands of airshow visitors to see the Catalina flying, being onboard as it swept across the North-East landscape was something I will never forget.