A toy helicopter flies forward with a force of 15 N into an oncoming wind of 10 N. The force of gravity pulls the helicopter down with a force of 5 N, but the propeller is providing an upward force of 10 N.

To analyze the forces acting on the helicopter, let's break down the forces involved:

1. **Forward forces:**
- Toy helicopter's forward thrust: **15 N**
- Oncoming wind resistance (force opposing the thrust): **10 N**

The net forward force can be calculated as:
\[
\text{Net forward force} = 15 \, \text{N} - 10 \, \text{N} = 5 \, \text{N}
\]

2. **Vertical forces:**
- Upward force from the propeller: **10 N**
- Downward force due to gravity: **5 N**

The net upward force can be calculated as:
\[
\text{Net upward force} = 10 \, \text{N} - 5 \, \text{N} = 5 \, \text{N}
\]

Based on this analysis:
- The helicopter is flying forward with a net force of **5 N**.
- The helicopter is also moving upward with a net force of **5 N**.

Thus, the option that accurately describes the helicopter's force is:

**The toy helicopter is flying forward with a force of 5 N and upward with a force of 5 N.**