The Commander of HMS Queen Elizabeth has strongly defended the need for such a ship, with questions raised over its cost and relevance in a changing world.
Despite the size of the aircraft carrier, Captain Jerry Kyd said it remains an "incredibly flexible tool" that was not only about war fighting, but deterrence, political signalling, disaster relief and humanitarian assistance.
Rapid developments in technology have led to discussions over the future of defence, with the likes of unmanned drones and cyber warfare, but the commanding officer believes HMS Queen Elizabeth and sister ship HMS Prince of Wales will prove good value over the next 50 years.
He said: "There is nothing that is invulnerable, whether it's a city, a car, an individual or a ship.
"We are not shy in the military to understanding risks and how to mitigate that in the theatre of war.
"These ships are expensive, absolutely, but look at all the major nations around the world, they all have an aircraft carrier capability. Why is that?
"The reason being is that (aircraft carriers) provide the government, very simply, with an incredibly flexible tool - it's not just about war fighting but deterrence, coercion, political signalling, providing a huge sea base for disaster relief and humanitarian assistance.
"This is why as a national symbol, not just of military power projection but British ambition and being a global outward facing country, it would seem odd as a maritime nation not to have a Royal Navy that could do that job for you.
"They are symbols of national power. They are totemic symbols of your ambition, your need to be an outward-facing global Britain, ready to play its full part in the western defence of democracy and security around the world. You can't do that with nothing.
"The investment in these aircraft carriers for me is logical, it's rock solid and a strategic necessity.
"I think it's a pretty good investment, £6 billion for two ships, I think in 50 years time we'll look back and think that was extremely good value because they will be used a lot."
Captain Kyd expects the ship to attract interest from a variety of onlookers during its sea trials, including Russian submarines which have been spotted around British waters in recent years.
"You don't sail an aircraft carrier of this scale without it attracting interest from all sorts of people," he said.
"That can be friendly people on the beach waving, through to other state actors when we're offshore to see how we're getting on, but we expect that and are used to it.
"Everyone watches everyone else in the defence game, but we're looking forward to it, the more interest the better."