Compatibility with more flight data APIs

[Splestule]

Goal

Enable Aether to fetch flight data from multiple API providers, not just OpenSky Network.

Background

Currently, Aether relies exclusively on the OpenSky Network API for live flight data. This creates a single point of failure and limits functionality when OpenSky rates limit requests. Supporting additional APIs would improve reliability and potentially provide richer data.

Potential APIs to support

Provider	Pros	Cons
ADS-B Exchange	Large coverage, hobbyist-friendly	Requires API key
FlightAware	Commercial-grade data, flight plans	Paid API
AviationStack	REST API, historical data	Paid tiers
Note: aviationStackService.ts already exists but is not actively used.

Implementation approach

1. Create a common interface for flight data providers
2. Implement adapters for each API
3. Add configuration to select primary/fallback providers
4. Handle API-specific data normalization

Relevant files

• server/src/services/flightService.ts - Current OpenSky integration
• server/src/services/aviationStackService.ts - Partial AviationStack implementation
• shared/src/types.ts - Flight data types

Acceptance criteria

• Abstract flight data provider interface defined
• At least one additional provider implemented
• Fallback logic when primary API fails
• Configuration via environment variables
• Documentation for adding new providers