With the proliferation of online review platforms, user reviews have become an important source of information to consumers about product quality. As a result, the word-of-mouth through online reviews can influence consumers’ purchase decisions and thus a company’s sales. Using the airline industry as a testing field, this study investigates whether online customer reviews can predict the sales of domestic flights or the company revenue of U.S. airlines. We compiled quarterly data from 2015 to 2018 based on three sources: financial reports of nine major U.S. airlines, domestic passenger data from the Bureau of Transportation Statistics, and online reviews of these airlines on the Consumer Affairs website. We found that the change in the number of reviews (volume) is more useful in predicting changes in revenue and the number of passengers than the change in the average rating (valence). Meanwhile, the predicted relationship becomes statistically insignificant when controlling for other factors such as seasonality. Further, we used sentiment analysis to create an average sentiment of the text of all the online reviews as an alternative measure of the average rating. We found that changes in the average sentiment is not a predictor of changes in airline revenue or the number of passengers. Our current findings and data limitations suggest a variety of promising avenues for future research, where we will expand the time period analyzed, cover a greater number of airlines, include international flights, account for layovers in routes, gather more extensive online reviews, and employ content analysis such as keyphrase extraction to identify trends in the topics of reviews.