Other scanners you might want to consider if you're interested in both civil/commercial and military aircraft are the Alinco DJ-X3, Icom IC-R5, Yaesu VR-120d and the Yaesu VR-500.
In the past, the spacing between airband frequencies has been 25kHz, however recently 8.33kHz spacing has been introduced in order to increase the number of frequencies available. Many new scanners are equipped to deal with this step. It should be noted that whereas commercial aircraft use the new 8.33kHz spacing, the military have so far stuck with the old 25kHz steps.
Some short wave frequencies are used for the long-range communications that occur during international flights. These frequencies are typically found within the ranges 2.85 - 18MHz and 118 - 137MHz.
It is important to point out that whereas buying and using a scanner is perfectly legal, it is actually illegal to use it for listening to aircraft frequencies. If you would like more information about how to abide by the law when using your airband scanner please visit the Ofcom website by following the link on the 'related sites' page.