In addition to expanding the capacity of flight services, alliances or strategic cooperation between airlines throughout the world are also used as a mean to increase the revenue of their alliance members. However, it is possible that expectations for increasing revenue and financial performance cannot be realized. Therefore, this study seeks to compare financial performance of 10 members of the SkyTeam alliance before and after joining the alliance. Data were collected from the Osiris database for the duration of 4 years before and 4 years after the inclusion to the SkyTeam. This study indicates that airlines in the alliance on average record a low profitability and liquidity ratios as well as a high gearing ratio which makes the company be at bigger financial risk of default. More often than not, sample data are drawn from a normally distributed population. Once data are confirmed normally distributed, paired sample t-test are used, otherwise Wilcoxon test are utilized. This study shows the significance level of each test and suggests that in most of financial ratios out of 20 ratios across airlines, financial difference before and after joining the strategic alliance is not significant. This finding which shows that the alliance has not met expectations is not surprising across other economic sectors. Future studies are needed in search of factors affecting alliance performance.