Section 4(2)(c) in The Rajasthan Ministers' (Travelling Allowances and Use and Maintenance of Conveyance) Rules, 1974
(c)for journey by air.-to one single standard air fare (inclusive of tax or surcharge on fare, if any) or actual cost of return ticket if a return ticket is purchased, plus incidental charges at the rate of 20% of standard air fare (excluding the element of tax or surcharge, if any) limited to the amount of one halting allowance.