Noun. 1. interleukin-any of several lymphokines that promote macrophages and killer T cells and B cells and other components of the immune system. lymphokine-a cytokine secreted by helper T cells in response to stimulation by antigens and that acts on other cells of the immune system (as by activating macrophages).
Now, passengers must pay a flat fee of $5.60 in each direction, no matter how many plane transfers are made to get from one city to another. For passengers flying a nonstop round trip, that means the fee will increase from $5 to $11.20.Passengers flying round-trip with a connection each way will see their fees increase $1.20 to $11.20 per round trip, versus $10 before the fee increase.ost of the new revenue will go to pay down the federal deficit. Until Monday, a passenger was charged $2.50 for each leg of a journey. For a nonstop round trip, the cost was $5. For a round trip with a connection each way, the cost was $10. The fee was capped at two flights each way.
U.S. government-assessed fee of $2.50 per U.S. enplanement per ticketed journey for security costs not to exceed $5.00 one-way or $10.00 round-trip (fees accrue incrementally with multi-segment travel itineraries).axes & Fees. Air Travel. The taxes and fees you pay are based on several elements and therefore, can vary widely. The airports you are leaving from and arrive at and the country those airports are in, all affect your taxes and fees.