The German air force is failing to meet Nato minimum training requirements because it does not have enough working aircraft for its pilots to fly, it emerged on Monday.

Almost half of the Luftwaffe’s pilots were unable to meet Nato’s target of 180 flight hours last year because their aircraft were grounded by maintenance issues.

Only 512 of the air force’s 875 pilots were able to meet the target, the German government admitted in a written answer to a parliamentary question.

The disclosure will add to concerns among Germany’s Nato allies over chronic underfunding.

“The Luftwaffe is at a low point,” Lt-Gen Ingo Gerhartz, the air force chief of staff, admitted at a defence industry event in Berlin last month.

“Aircraft are grounded due to a lack of spare parts, or they aren’t even on site since they’re off for maintenance.”

It emerged in February that on average only 39 of Germany’s 128 Eurofighter jets and 26 of its 93 older Tornado fighters were available for combat or training last year.