This study examined the extent to which relations between students' perceptions of the learning environment, academic achievement, and study approaches measured by both self-reported and process data were consistent amongst 323 engineering students in a flipped classroom course. A hierarchical cluster analysis on four self-reported scales identified deep and surface study approaches. Students reporting deep approaches obtained significantly better marks than those reporting surface approaches. An agglomerative sequence clustering on sequences of students' online interactions found four observed study approaches: two focused on content and two focused on assessment. Students adopting content-focused approaches performed significantly better than those employing assessment-focused ones. Two cross-tabulations revealed consistency of relational patterns between perceptions of the learning environment and study approaches by self-reported or process data. Amongst students with better perceptions, a significantly higher proportion of them reported deep approaches than surface approaches. Amongst students using content-focused approaches, significantly higher proportions of them held positive perceptions than negative perceptions. The study results suggest to teachers that fostering a better learning environment, helping students understand how online and in-person components are integrated, and equipping them with knowledge and principles of flipped classroom learning would be useful to enhance students' learning experiences in flipped classroom courses.