public static int FindFirstFreeID(BusinessFlight[] InputArray){
		int ActiveID = 1000;
		int SafeID;
		int[] IDCollection = new int[InputArray.length];
		for (int i = 0; i < InputArray.length ;i++){
			IDCollection[i] = InputArray[i].FlightNumber;
			// Builds a collect of the ID's in the database.
		}
		
		for (int i = 0; i < IDCollection.length ;i++){
			if (ActiveID == IDCollection[i] ){
				// that number is taken here.
				ActiveID ++; // Increase number we are checking for. 1000, 1001, 1002 etc.
				i = 0; // Reset checking array. Start from the beginning again.
			}
			else{
				// that number is not taken here.
				// Keep checking the array.
			}
		}
		// Check has completed on the ActiveID.
		SafeID = ActiveID;
		return SafeID;
		
	}