That is the subject of a new paper by Joel Waldfogel and Paul M. Vaaler, here is the abstract:
While product differentiation is generally benign, it can be employed to discriminate against customer groups, either to enhance profitability by appealing to discriminatory customers or in unprofitable ways that indulge owners’ tastes for discrimination. We explore discriminatory product differentiation in the airline market through airlines’ depiction of Israel on their online route maps and whether their online menus include kosher meal options. We first show that several international airlines omit Israel from their online route maps. Three of these airlines are members of the major international airline alliances. With data on over 100 airlines, we then document that Israel map denial is more likely for airlines with passengers from countries exhibiting greater anti-Semitism. Owner tastes also matter: denial is more likely for state-owned airlines in countries that do not recognize Israel. Kosher meal options on online menus follow similar patterns, suggesting anti-Semitic rather than anti-Zionist motivations. Israel denial does not reduce the probability of alliance membership with alliance leaders having few airline alternatives to choose from in the Middle East.
For the pointer I thank the excellent Kevin Lewis.