Want to reach affluent households? Try the in-flight magazines. In an annual rite of spring, magazine publishers and advertisers alike are spending this week with newly released research by MRI, Mediamark Research. Among the leaders in reaching readers with high household income are the in-flight magazines. Two of the titles boasting the highest household income are United's Hemispheres with $119,588 and American Airlines' American Way with $100,026. Southwest Spirit also scores well with an average household income of $93,916 for its readers, while Continental's in-flight audience has an average household income of $86,867 for all adults (but gets over the $100,000 mark for men, at $104,100). In-flight magazines have long performed well for brand and direct response advertisers alike, have a wide pass-along readership and allow advertisers to tap into a captive audience.