public int reserveHighestInClass(boolean firstClass) {
		if (firstClass) { // If the user chose first class:
			for (int i = 0; i < this.numFirstClass(); i ++) { // Loop through all the seats in first class
				if (this.seats[i] == false) { // If the seat at index i is available:
					this.reserve(i + 1); // Reserve seat number i + 1
					return i + 1; // Return the number of the reserved seat
				}
			}
		}
		
		else { // If the user chose economy:
			for (int i = this.numFirstClass(); i < this.seats.length; i ++) { // Loop through all the seats in economy
				if (this.seats[i] == false) { // If the seat at index i is available:
					this.reserve(i + 1); // Reserve seat number i + 1
					return i + 1; // Return the number of the reserved seat
				}
			}
		}

		return 0; // Return 0 if the plane is full
	}