A BAE air battlecruiser starts a new arms race

How would the world respond if BAE Systems demonstrated a flying battlecruiser in 2018 armed with lasers, close-in defenses, and hypersonic missiles?

Britain and the United States would buy early examples while France, China, and Russia pursued rivals, and navies would develop long-range missile counters and aerial escorts.

This scenario begins with BAE demonstrating a vehicle it can manufacture. British and American purchases are expected, while France, China, and Russia would pursue rivals or counters. Long-range missiles are suggested as a response to a large airborne target, with their effectiveness against its fictional defences left uncertain. Its armament could threaten carrier groups and encourage fleets to acquire flying escorts of their own. Maintenance, training, and the need to keep some ships available would still shape purchase numbers. The extravagant cost estimates and order sizes are part of the participants' speculation.