All Cisco Aironet wireless access points and bridges currently being shipped run IOS. The only exception is the OEAP602.
Note:- Some older Cisco access points did not run IOS, such as the Aironet 340 which ran only VxWorks, and the 1000 series lightweight APs. Access Point IOS is distributed as a tar file. These tar files can be downloaded from cisco.com SDS; lightweight IOS images (k9w8) are also bundled in the WLC software images (.aes.) The IOS image names include the following components:- platform-featureset-tar.version.tar
platform- the access point hardware model or family supported by the image
ap1g1 - 700 series (702w beginning with 15.2(4)JB5)
ap1g2 - 1600 series
ap1g3 - 1530 series
ap3g2 - 3700/3600/2700/2600/1700 series
ap3g1 - 3500/1260 series
ap802 - AP embedded in 819, 812, 886VA-W/887VA-W, and C88x routers
ap801 - AP embedded in 861W, 891W, 1911W routers and most 88xW routers
As AP IOS is always distributed as a tar file, the AP cannot directly execute such a file (thus, if you were to copy c1240-k9w7-tar.124-25d.JA1.tar directly onto AP flash, and then try to boot it, this could not work.) The tar file contains, in addition to the IOS image proper, the radio firmware files, the HTML GUI files (if present), and various other files.