Island warning time before air power

Britain's island position bought time for defense, while the sea itself offered no automatic shield. In 1805, an invader had to fight through maritime barriers whose resistance warned the government and allowed forces to assemble. Aircraft and airborne assault made that older buffer seem less reliable in World War II, particularly after the invasions of Norway and Crete. Those campaigns did not prove that Britain faced identical conditions, because an alert government and a stable chain of command still mattered. The comparison clarifies why Napoleon's sailing-era invasion could not conceal the naval battles and preparations that preceded a landing. Coastal fortifications mattered as obstacles and as mechanisms for consuming the invader's time.