Escort carriers and shore-based aircraft tighten convoy defense

Escort carriers extended air cover toward the convoys, while shore-based aircraft made the approaches to Britain increasingly dangerous for U-boats. Submarines were pushed toward the mid-Atlantic, where they still could not reliably predict a convoy's route. Aircraft operated alongside surface escorts, intelligence, and improving sensors, so every added layer reduced the space in which U-boats could search and attack safely. The defense became stronger through the interaction of these systems rather than through one decisive weapon or ship type.