u.s. congressional proposal would eliminate income tax exemptions certain airlines could affect major gulf carriers potentially worsen international spat u.s. airlines middle east rival u.s. airlines petition federal government years intervene see unfair competition three major gulf carriers proposal tuck deep senate tax-cut plan call airlines headquarter foreign countries pay u.s. incorporate tax rate carrier home country income tax treaty unite state carrier country origin few two arrivals departures per week operate major u.s. airlines airways emirates emira.ul etihad airways years accuse u.s. competitors illegally subsidize governments gulf carriers deny accusation could immediately reach comment thursday proposal pass could leave gulf carriers vulnerable home countries unite arab emirates qatar income tax treaties unite state accord internal revenue service website number nations could possibly also affect time perceive discrepancies u.s. trade agreements face critical eye u.s. corporations federal government language senate proposal set stage crackdown tax leniency airlines would likely well-received american carriers years petition u.s. government intervene dispute u.s. tax treaties entities foreign countries either exempt pay reduce rate income vice versa u.s. entities abroad reciprocity agreements however less formal deal fall short official accord accord tax attorney sam brotman brotman law reciprocity agreements usually countries necessarily 100 percent friendly u.s. brotman say thursday call handshake deal bill word stand ramp already tense battle u.s. airlines gulf carriers addition introduce u.s. senator johnny isakson georgia delta air line dal.n one vocal critics gulf carrier practice headquarter atlanta spokeswoman isakson mention gulf airlines provision support american job provide level play field mutual fairness international passenger aviation isakson spokeswoman marie gordon say email thursday foreign airlines receive preferential tax treatment countries choose open market u.s. company delta decline comment gulf carriers may focus foreign airline u.s. tax exemption cut