Two more remain in police custody and must either be charged or released within hours, their 28th day held without being charged with an offence.
Under British anti-terror laws, suspects can be held for up to 28 days without being charged, subject to regular court approval.
"Two men were this evening, Wednesday 6th September, charged in connection with the anti-terrorist operation overnight on 9-10 August 2006," a police spokesman said.
Donald Douglas Stewart-Whyte and Mohammed Usman Saddique are charged with "the intention of committing acts of terrorism engaged in conduct to give effect to their intention to smuggle the component parts of improvised explosive devices onto aircraft and assemble and detonate them on board."
Mr Stewart-Whyte is also charged with having illegal firearms in his possession.
Both men are due to appear in Westminster Magistrates' Court on Thursday morning.
The two men bring the total number of suspects charged in connection with the plot to 17.
They were among 25 people arrested since police staged pre-dawn raids on August 10 in London and towns and cities around Britain. Six have since been released without charge, including Wednesday's release.
Eleven of the remaining 15 face the most serious charges of conspiring to murder and preparing acts of terrorism.
Four others are charged with lesser offences, including withholding information about an impending terrorist attack and possessing items and information likely to be useful to someone planning an attack.
The suspects were allegedly planning to smuggle seemingly innocuous liquids on to planes with the intention of assembling them into bombs on board.
The alleged plot was described by one senior police officer as "an attempt to commit mass murder on an unimaginable scale".