Solution

According to IFRS 15, contracts should be combined and accounted for as a single contract if they are negotiated as a package with a single commercial objective, the amount of consideration in one contract depends on the price or performance of the other contract, or the goods or services promised in the contracts are a single performance obligation.

In the case of the airplane manufacturer, it seems that the two contracts – one for designing and manufacturing new fighter planes, and the other for supplying parts for existing planes – serve two different purposes and likely have two distinct commercial objectives.

They also seem to be separate performance obligations, as designing and manufacturing new planes and supplying parts for existing planes are distinct activities that the manufacturer is promising to perform. Additionally, it doesn't seem like the consideration in one contract is dependent on the price or performance of the other contract.

So, based on the information given, these contracts would not be combined under IFRS 15 and would be treated as separate contracts. However, the final determination would depend on the specific facts and circumstances of the contracts.