NetJets is suing the IRS over a tax bill totaling $642.7 million, money the fractional jet provider says it never should have been required to pay in the first place.The Internal Revenue Service improperly assessed passenger ticket taxes, NetJets said in its complaint in federal court in Columbus, Ohio. Four NetJets subsidiaries involved in the lawsuit – NetJets Aviation, NetJets International, NetJets Large Aircraft and Executive Jet Management EJM – argue that the ticket tax should apply only to passengers who use commercial or charter aircraft owned by others. NetJets sells or leases shares of business aircraft to individual owners and companies.