In February Air Force Secretary Deborah Lee James revealed the first concept image of the futuristic B-21 long range bomber, which will be built by Northrop Grumman. Previously known as the Long Range Strike Bomber (LRS-B), it will be the U.S. military's first bomber of the 21st century.

It will be able to launch from the continental U.S. and deliver airstrikes on any location in the world. The new B-21 also reaffirmed that, after more than 100 years the bomber, remains a crucial part of the U.S. Air Force's offensive arsenal.

"The B-21 will offer the ability to bring weapons to bear quickly," Wayne Plucker, aerospace and defense director at research firm Frost & Sullivan, told FoxNews.com. "It can load up and take off without refueling and restaging, and that can make for a world of difference in modern conflicts."

Going the distance

Today the long-range bomber is very much a purpose-designed and purpose-built aircraft that evolved over time, yet the bombers actually pre-date the First World War.

"Military planners thought about bombing targets at a distance before the airplane was even invented," Jeffrey Underwood, military historian at National Museum of the U.S. Air Force in Dayton, Ohio, told FoxNews.com. "The concept goes way back to the days of the balloon."

The first use of bombs being dropped by an aircraft is generally accepted to be when the Austrian military used balloons against Venice in 1848.

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"Some sources say they dropped only two bombs, but others said it was as many as 200 bombs," Underwood told FoxNews.com. "While it was probably closer to two, this was still the first aerial deployment of bombs."

The first time an airplane was used to drop bombs on the enemy also pre-dated World War I. This occurred in Libya when Italian pilots dropped hand grenades on Turkish Lines during the Italo-Turkish War (1911-1912). While only occurring on a small scale in a very remote conflict this foreshadowed the use of aircraft to drop larger, purpose-built bombs during the First World War.

"Military planners already were thinking of the possibilities of how an aircraft could deliver a bomb to target," said Underwood. "The British built a bomber aircraft that was shown in Paris in 1913, but it proved not to be so successful in the early stages of the (First World) War."

Instead it was the Italians and Russians that developed pioneering bomber aircraft. However, neither nation had the industrial capacity to produce the aircraft in large numbers, and by the end of the war the potential for very specific aircraft – including fighters, reconnaissance and bombers – was understood. The age of the bomber as an offensive weapons platform had arrived.

Strategic bombing

The U.S. was late to enter the First World War, and just as it had with tanks, artillery and other equipment, the U.S. military relied on what its allies developed. The United States actually produced the Italian Caproni Ca.3 under license, but military planners such as General Billy Mitchell saw the potential for bombers. By the early 1920s the first American-designed bombers were taking flight.

The Martin NBS-1, and the improved Martin MB-1, were among the very first specifically-built U.S. bombers and paved the way for other bombers.

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More importantly, bomber tactics also developed in the interwar period. Some military planners argued that the bomber could be used to take out an enemy's industrial capabilities, while others thought it could be used as a terror weapon against the enemy's civilian population.

"The idea of bombing civilian targets was considered quite horrific to many people in the 1930s, but by 1944 after the horrors of the Second World War there was a general acceptance to bomb enemy cities," added Underwood. "We think of how atomic warfare was so scary in the Cold War, but in the 1930s there was real concern of enemy bombers targeting population centers."

The sky’s the limit

Throughout World War II bombers increased in size and range, but one fact still surprises many people who only know of the relative comfort of commercial air travel – namely that, even in 1945, bombers weren't pressurized. Pilots and crews wore leather flight jackets to stay warm!

"It was only at the end of World War II with the introduction of the B-29 that changed the way the crew dressed," Underwood told FoxNews.com. "Early in the war the crews of bombers like the B-17 and B-24 had to suit up in layers, even in the Pacific, but by the end of the war the crew could be in short sleeves. That allowed the bomber crew to be much more effective and the bombers could now fly well above fire from enemy anti-aircraft guns."

As the ceiling of the bombers increased, so too did the range. The B-36 Peacemaker, which was developed during the war, was designed to fly from New York to Berlin. The next leap forward was with aerial refueling that could allow crews to fly around the world. This allows U.S.-based bomber crews to drop bombs on targets in the Middle East and further.

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In 2015 a pair of B-52 bombers flew non-stop from Louisiana to Australia as a simulated run to show that U.S. bombers – with two crews onboard working in shifts – could travel all the way to China.

Old war birds still flying

What makes the announcement that the B-21 will enter service in the next decade so notable is the fact the U.S. Air Force's bomber fleet is old enough that many of today's pilots are actually younger than the planes they fly.

"The B-52 has been flying for six decades," Frost & Sullivan's Plucker told FoxNews. "As a former B-52 driver it was old when I was driving it, but today there are literally grandchildren flying the aircraft their grandfathers had flown."

The B-52 won't fly off into the sunset just yet, even with the B-21 coming up. The B-52 Stratofortress has kept flying even as the B-1 and B-2 bombers have been added to the Air Force's arsenal.

"The B-52 will likely be in service until 2042 at least," added Plucker.

Ironically, the B-52 stayed in service because of cost concerns of the B-1, and the fact that it wasn't really considered in the 1970s to be a significant upgrade. In the 1976 presidential election, then candidate Jimmy Carter called the B-1 program a waste of taxpayer dollars. With the election of Ronald Reagan, the B-1 program was pushed forward – as a temporary fix until the Advanced Technology Bomber, the eventual B-2, could be developed.

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"Today the B-1 is actually still cheap at twice the original price," Plucker told FoxNews. "As the B-1B, it is also the workhorse of the Air Force."

The bomber's future

The question has been brought up as whether the U.S. Air Force even needs a next generation of bomber – the B-21 or any other plane – given the advent of drones and missiles fired from cruisers and other systems.

"The bomber remains very much part of an offensive payload, and it is still developing technologically," Ben Goodlad, principal weapons analyst at IHS Aerospace, Defence and Security and editor of IHS Jane's Defence Insight Report, told FoxNews.com. "There is nothing that can replace a bomber. The bomber has greater survivability against increasing threats, while the payloads are increasing and the range."

The counter point might be that a bomber's role in peacetime is more limited than an aircraft carrier, which can fill a role in humanitarian missions. The bomber’s roles are as a deterrent and offensive platform.

"It really doesn't have a peacetime role," Plucker told FoxNews.com. "It is about combat and messaging, that is about it in its realistic role. But that is enough to keep the bombers flying."