To calculate the number of license plate combinations between AAA-000 and ZZZ-999, we consider that there are 26 letters (A-Z) for each of the three letter positions and 10 digits (0-9) for each of the three digit positions. This gives us (26^3 \times 10^3 = 17,576 \times 1,000 = 17,576,000) possible combinations. Therefore, there are 17,576,000 unique license plate combinations in this range.