Item								Prio
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* Increase goto altitude accuracy (ALT xyz)			Med
* Implement weather subsystem (use existing stubs)		Low
* Rewrite command parsing					Med
* Implement Conflict Alert (CA; conflicting trajectories
  checker)
* Implement Minimum Safe Altitude Warning (MSAW; plane flying
  too low)
* Implement System Coordination (SYSCO; negotiate the release
  of flights from sector to sector)
* Implement Area Penetration Warning (APW; aircraft in
  restricted area warning)
* Implement Arrival and Departure manager
* Implement communication breakdown
* Implement emergency situations
* Implement nav beacons
	* ILS							High
	* VOR							High
* Kill FIXMEs							High