1. st stage: Participants will receive information about the study, complete measures of fear of flying and emotional variables, and undergo a diagnostic interview for flight phobia and additional disorders.
2. nd stage: During the week prior to treatment, participants will complete a brief measure of emotion-related variables every evening at a fixed time (08:00 pm).
3. rd stage: Participants will receive therapy for fear of flying using a Virtual Reality (VR) simulator. Therapy sessions will be held once a week during 4 weeks. Participants will complete a brief measure of emotion-related variables at a random time during the 12 hours before the therapy session at a random time during the 12 hours after the therapy session. This will occur for every therapy session.
4. th stage: After treatment, participants will complete measures of fear of flying and emotional variables.

1. st stage: Participants will receive information about the study, complete measures of fear of flying and emotional variables, and undergo a diagnostic interview for flight phobia and additional disorders.
2. nd stage: During five weeks no therapy will be administered. Participants will fill questionnaires as follows: During the first week, participants will complete emotional measures every evening at a fixed time (08:00 pm)
3. rd stage: During each of the following 4 weeks, participants will complete two emotional measures during a 24 hour period.
4. th stage: Participants will complete measures of fear of flying and emotional variables.

VRET will include 4 weekly 1-hour sessions over the course of 4 weeks. The treatment protocol is based on the Virtual Reality (VR) treatment manual guidelines (Rothbaum & Hodges, 1997,1999) and includes psychoeducation, anxiety management training, cognitive restructuring and exposure. The first therapy session focuses on creating an individually-tailored conceptualization and treatment plan. Following this process, participant and therapist conduct a short introductory VR flight exposure simulation to familiarize the participant with the VRET apparatus. The VRET apparatus is an advanced, large-scale VR system that allows maximal immersion within the virtual environment. The second, third and fourth sessions include psychoeducation, relaxation training, cognitive restructuring and individually-tailored VR exposures (the therapist can manipulate the turbulence level and other flight-related variables to fit participants' fears and current progress).

The Flight Anxiety Situations Questionnaire (Van Grewen, Spinhoven, Van-Dyck, & Dikstra, 1999) is a 32-item, 5-point Likert-scale (1= no anxiety to 5=overwhelming anxiety). The FAS evaluates flight-related anxiety in various situations. We used the total score of the FAS which ranges from 32 to 160 with higher values indicating more flight-related anxiety. Thus, higher values reflect worse outcomes, and lower values reflect better outcomes. The total score is obtained by summing all items.

The Flight Anxiety Modality (FAM) questionnaire (Van Grewen et al. 1999) assesses somatic and cognitive aspects of Flight Phobia. It includes 18 items that are rated using a 5-point scale (1=not at all, 5=very intensely). We used the total score of the FAM which ranges from 18 to 90, with higher values indicating more flight-related anxiety. Thus, higher values reflect worse outcomes, and lower values reflect better outcomes. The total score is obtained by summing all items.

Participants randomized to receive 4 weekly 1-hour sessions sessions of VRET (Virtual Reality Exposure Treatment). Number of participants: 42.

Participants randomized to waitlist (did not receive treatment for 4 weeks). Number of participants: 42.

The Flight Anxiety Situations Questionnaire (Van Grewen, Spinhoven, Van-Dyck, & Dikstra, 1999) is a 32-item, 5-point Likert-scale (1= no anxiety to 5=overwhelming anxiety). The FAS evaluates flight-related anxiety in various situations. We used the total score of the FAS which ranges from 32 to 160 with higher values indicating more flight-related anxiety. Thus, higher values reflect worse outcomes, and lower values reflect better outcomes. The total score is obtained by summing all items.

Participants randomized to receive 4 weekly 1-hour sessions sessions of VRET (Virtual Reality Exposure Treatment). Number of participants: 42.